Scoring
If you've already played devil daggers, you'll probably feel weirded out by hyper demon's scoring system at first. You don't need to survive as long as possible to advance in the leaderboards: you need to score by killing enemies in a quick succession. You are losing points at a steady pace at all times, but killing enemies gives you points back, and killing a lot of them very quickly will give you even more points.

Shooting
You can hold left click to fire a constant stream of daggers, or tap left click to fire shotgun shots. With right click you can grab big gems and green bombs (more on this later).
https://youtu.be/UiDBc_AKaoc?t=1

Movement
If you press space, you jump. If you press space while in the air, you will either do a dash if you're pressing any of the directional keys, or do a stomp if you're not moving (note that the taller your height is, the bigger your stomp radius is as well). You can also slide if you hold the spacebar while dashing, and finally, you can dodge enemy attacks by pressing space while an enemy has glowing eyes.

https://youtu.be/HUUvfL5XYdc

Damage upgrades
After you've killed enough enemies, a damage upgrade will appear in the center of the arena. You can pick it up by just going through the upgrade beam, and you'll get extra ammo for your shots. It's exactly like picking gems off the ground, with the blue upgrade giving you 10 ammo gems, and the orange upgrade giving you 20 ammo gems.

You can also suck it in with right click and get an extremely powerful laser shot (sacrificing the upgrade). At first this seems like a bad choice but it's actually the best thing to do.

https://youtu.be/0BYy5criPAg


Gems
All of the enemies (except spawners and small skulls) drop gems when you kill them. Also, if you're firing daggers, the gems will stop dead in the air. Once you stop firing, they'll all go flying to you. So take that into account if you have to decide between picking the gems up or sucking them in (more on this later). When you pick them up, you shoot extra projectiles when you fire. The amount of extra shots you have left will be indicated by the gems around your wrist.

https://youtu.be/NmGH48QZ808

There are also big gems dropped by the spawners that you can grab with right click to move around as you want, or shoot to get 3 small gems. If you grab it, you can use it as a shield, it will protect you from 1 attack and then it'll break without dropping any small gems. They also have 2 offensive uses. First, you can dash through them. This can be used to gain height very quickly, or also to kill scuttles by dashing through them (even if they aren't stunned). The other offensive use is to shoot at the big gem with a laser, releasing homing projectiles everywhere. I'll try to explain this better in the next section of the guide, since i haven't even begun with the laser yet.

You can also suck the small gems in while holding right click, and shoot a laser after releasing right click (the most fun option). The amount of gems you suck in is very important, since it determines your damage output and which enemies you can kill.

https://youtu.be/Iqg99WG64qA

Since the laser is such an important part of the game it deserves its own section entirely.
As said earlier, you can suck gems in holding right click, which will allow you to fire a laser.
Regardless of the amount of gems you suck in, with the laser you can 1shot some enemies like snakes (by shooting them in the head) or spawners (by shooting at the big gem inside it). You can also shoot at the green bombs, which will increase the explosion radius.

https://youtu.be/SuDtCIMqwao

But the best way to kill enemies in a quick succession is by always trying to suck in at least 3 gems, which will allow you to kill almost any group of enemies. Not because you'll get a damage output to your laser, but because you'll be able to ricochet the laser off the ground and fire at multiple enemies at once.
You can go to the training menu to try this out. The most important thing about the ricochet is that you get a sound cue indicating you're about to hit the ricochet correctly. If not, you'll just shoot a laser at the ground and waste gems, so it's pretty important.

https://youtu.be/yA5SgR20AvA

You can also suck in multiple small gems even while they're getting sucked in by the spiders. You just need to hold right click, look at each gem individually and press left click each time the purple highlight comes up. This is great for gathering at least 3 gems without needing to go kill the spider.

https://youtu.be/nwl63n2j6Fs

One thing that the game doesn't even tell you in the training section, is that you can chain laser shots incredibly fast. The best way to try this is to shoot a laser at a snake's head, and immediately start holding right click again. By doing that, you can instantly suck in the gem of the snake you've killed and use it for a laser shot. You can chain this with any other thing that dies of 1 laser shot and drops gems, like big skulls or stunned scuttles.

https://youtu.be/2sx2Jrz8_yk

It's time to talk about the big gems now. First off, you can start a ricochet kill chain by grabbing a big gem, looking at the ground, dropping it and immediately holding RMB. When you drop it while looking at the ground, the big gem will break, and by holding RMB after that you'll instantly store 3 gems for a laser.

https://youtu.be/QZA7r_KVrgg

You already know that you can get 3 small gems by breaking them (which is fine) but you can also do something much cooler. By shooting at a big gem with a laser, it will explode and send homing shots flying everywhere. The more gems you've sucked in for the laser shot, the more homing shots there'll be.

https://youtu.be/Lfh42PGS_Kw

Remember how you can sacrifice the damage upgrades by holding right click while going through it and getting a powerful laser shot instead? The best use for this laser is to shoot it straight at a big gem. Since the shot is so powerful, the homing shots from the big gem will go flying everywhere and killing a ♥♥♥♥ ton of enemies. This is extremely useful for getting a lot of points really quickly. You can also grab/drop the big gem by holding/releasing left click while you're holding right click. You can even do it while charging a laser, so you can go grab the damage upgrade laser, grab a big gem, drop it in front of you and the release the laser.

https://youtu.be/qYvDD8vHlTQ

If you manage to hit a big gem using the second upgrade laser (the orange one) you can try to rail as many scuttles as possible. This is probably the strongest homing attack in the game, so all scuttles will be stunned. You need to take advantage of this by rail chaining, lasering one stunned scuttle after another. The most tricky part about this is getting the chain started: after you shot at the big gem, look for a small gem ASAP and suck it in. Then you can start the chain on any stunned scuttle.

https://youtu.be/9JzjEfcgVhI

There's also a better but harder way to take advantage of the gold upgrade homing attack. Instead of railing each stunned scuttle, you should dash through as many of them as you can while holding left click (this will stop you from picking the gems up as ammo and leave them floating). When the slow-mo is about to end, look for the nearest spider and kill it (if you're lucky, the spider will be dead from the homing attack and you can skip this step). After that, kill the spawner, suck all the small gems in, and shoot a laser at the big gem. You'll get a ton of homing shots and there will be a lot of stunned scuttles again, so you can keep this cycle as long as you can (specially useful for 300+). Homing attack -> Kill scuttles -> Kill spider -> Kill spawner -> Homing attack...

https://youtu.be/fuhHvDNKEAA

You can see the enemies glitched out when they are about to spawn. You can go through them in this state but if you're inside you'll die as soon as they spawn. So just watch the "holograms" to choose which enemy you want to kill next.

Spawners
The first enemy in the game. The name is pretty obvious: it spawns enemies (a group of small skulls and a big skull) and holds a big gem inside. If you kill it quickly enough, no skulls will spawn. The best way that i know to do this is to hold left click at first and then firing a shotgun shot like 2 seconds later.

https://youtu.be/80yJ_SJdzPc

The fastest way to kill it without losing the gem is with lasers: if you've sucked at least 3 gems in, aim at the ground in front of the spawner (and in front of you) until you hear the ricochet sound cue, and release the laser.

You can also instantly kill spawners in 2 different ways.

The first way is to shoot at the big gem inside of it with any amount of lasers, but beware: you will lose the big gem if you do this. It can be very useful if you're getting swarmed and need to kill spawners quickly, but avoid it if you can since getting the big gem is very important too.

The second way is to dash through the big gem. To do this safely, you should be at least 2 rocket jumps high in the air. Any lower than that and you'l probably just get killed for touching the spawner.

Small skulls and big skulls
Small skulls follow you around. You can kill them with almost anything, but you already know that. The only useful tip i have for this is to just go in circles like in devil daggers to avoid getting swarmed with skulls. If you keep going in circles, they'll probably never catch up.
Big skulls are like small skulls, but much faster and drop a gem after death. You should also go in circles to avoid them but they'll catch up to you a lot easier than the small skulls, so be careful.
https://youtu.be/tR7N_Z0V4Yc

-Scuttles [UPDATED]
The most annoying and dangerous enemy in the game besides the snakes. When you damage them they get stunned for a moment, and if you're close to them, as soon as they recover they'll go flying in the air and then try to kill you EXTREMELY quickly. So be very cautious when near stunned scuttles. These mf's can also kill you while they're stunned if they fall on top of you while you're standing on the ground. The best way to counter this is to jump, dash or slide: being in the air, dashing or sliding makes any stunned scuttle that touches you die in an instant.

The easiest way to deal with them is with the ricochet. If you have 3 gems sucked in and aim correctly, you'll stun the 3 scuttles at the same time. As soon as you do this, you need to dash and slide to the scuttle nearest to you. As soon as you touch one while sliding you'll fly straight up to the air, and that's when you need to dash and slide again. That way you can kill them with 3 smooth slides. You can also hold right click while you're doing this, to suck in their 3 gems for a laser instead of picking them up as ammo.

https://youtu.be/0XiybI-Ut6o

That being said, this can sometimes be dangerous. If one of the scuttles is too far from the other two and you know you won't slide there in time, just start shooting at it to keep it down and eventually kill it if possible.

The fastest (but hardest) way of dealing with them is to dash through a big gem and then dash through the 3 scuttles (even if they aren't stunned) consecutively. To do this: grab a big gem with right click, jump, and then drop it with left click and dash at the same time (space + left click) while moving forward. Then just dash through the 3 scuttles as you would do if they were stunned.

https://youtu.be/v0ju_78FJTc

Snakes
Very dangerous. They cover a lot of the arena and can kill you very easily. The best way to avoid them is to rocket jump as high as you can, but to kill them you need to shoot them in the head. If they're not looking at you, just keep shooting and eventually they'll turn around and be much easier to kill, either with normal shots or laser/ricochet shots. They'll also always go around the damage upgrades, so if you see a damage upgrade beam coming up, you should probably start rocket jumping in advance to avoid them in the future.

https://youtu.be/Bvjoc_9sisg

You can also stun them with a stomp if you're about 2 rocket jumps high. It's pretty useful because once they're stunned, you can pretty easily kill the 3 heads with one shotgun shot. You should know though that if you stun them, they will rise their heads from the ground for a moment, so you should be aiming higher than normal after you do the stomp. A great way of easily stunning them is to just do a 3 scuttle dash combo, and as soon as you've jumped over the last scuttle, do a rocket jump in the direction of the snakes and do a stomp.

https://youtu.be/34hDY1OKHUc

Spiders
They hold 3 gems that you need to shoot in order for them to die. While they're alive, they'll suck in all the gems in the air. After sucking 3 gems in, they'll drop a green bomb, which you can grab with right click to throw around or shoot with a laser to instantly kill the spider and anything near it with the explosion. It's kind of a good payoff for losing some gems, but since they make sucking gems in for yourself a lot harder (you have to grab each gem individually instead of sucking them in all together) it's always best to kill them when possible. There are two main ways to kill them.

You can dash+slide under them and get behind them. They'll immediately drop to the ground and start facing their gems towards you. If it's in the ground, once you shoot at 1 gem, it will turn around and start facing you with another gem, so it makes killing them very easy since you only need to keep firing at their gem (it's always the same spot).

https://youtu.be/e32beV8oGwQ

Or you can kill them in a more stylish and efficient way: ricochet. If you have 3 gems sucked in, you can dash+ slide under the spider, but as soon as you're below it, move the camera to the ground and release right click WHILE you're sliding. It may be tricky to pull off at first but it's very satisfying once you get the hang of it.

https://youtu.be/tMopbW9e_-E

Extra note: you can instakill spiders with a green bomb by just throwing it below them, kinda aiming at their legs.

Centipede[UPDATED]
It will show up after you've killed enough enemies. It's very dangerous since it moves fast af, but the good thing is that all other enemy spawns stop as soon as it comes out. So when you see it, try to kill all other enemies first to then deal with it safely.

The easiest way to deal with it is to stand still and scrape it while it rises its head. Then, pay attention to where it's heading, because it will turn around and try to kill you. If it turns to the left, then walk slowly to the right while you're scraping it, using its own body as a shield. And if it goes right, do the same thing but left.

https://youtu.be/U--wRplci-c

After the centipede dies, you have a great oportunity to deal a ton of damage with its head. You can either break it and get a bunch of gems, or you can rail it to get a special attack called "stormrail". Do whatever you want with it, but imo the easiest thing to do is to break it and then use those gems for a homing attack. If you want to do this strat, you should do the following: break the head and start shooting constantly so you don't pick up the gems as ammo by accident. While you're doing this, go and look for the spider that just spawned, and kill it (without railing it). Then, go look for the spawner and break it. If you did everything correctly, you should have the gems from the centi head and the 3 gems from the spider floating in the air. Suck those gems in with right click and rail the big gem from the spawner you just killed. This will do a massive homing attack.

https://youtu.be/4Xl_fcTu36w

A while after the second damage upgrade, the boss (giant trippy sphere thing) will appear in the sky. You don't have to actually fight it once it appears though, you need to kill a few more enemies until you can actually damage it. The fight will start once it covers the center of the screen and everything else disappears. When this happens, you should be very quick and suck in a gem immediately so you can prepare to rail it.

Before learning how to damage the boss, you should know that as soon as the fight starts, you need to start dashing backwards. If you don't, it will suck you in and you will die. Even if you do dash backwards, if you don't damage it quickly enough you will get sucked in anyways and die.

To damage the boss, you need to shoot at the black orb that moves erratically. Once you kill an orb, another one will appear, and so on until you kill 6 orbs. Each one drops a gem once it dies, so you can instantly suck it in and rail the next one. But be careful: if you take too long to aim, you will get sucked in and die.

The problem is that each time you rail it, it starts pulling you in faster. A good strat to counter this (credit to Pride in the HD pals) is to kill the first 3 orbs with a rail, and then the 4th with a shotgun. After the shotgun kill, rail the next orb, and for the last one, wait until you're very close and release the laser. If you try to aim quickly you'll probably miss since it will be moving extremely fast.

https://youtu.be/Yuz59RDtZZw

extra tip: you can prefire the first orb before it even appears (you can see when to do it in the video)

Since the endgame (everything after gold upgrade) is so chaotic, the best thing you can do is to nail the early game. If your early game is slow, you won't have much room for error in late game, and you probably won't get 350+. If you're getting 140+ after killing the centipede, then your early game is fine, at least for 350. But again, the faster your early game is, the easier the late game becomes, so you should always try to improve it more, at least until 155ish after centi.

If you check out the top 10 replays, you'll see that pretty much every run begins the same way. At least until the second spawner appears, you should follow a specific kill order.

First: fresh spawners are always a number 1 priority, at least until the gold upgrade, since the skulls they spawn can kill you very easily and distract you from quickly chaining ricochet kills. To prevent this from happening, start holding LMB, take a step back, and wait until you hear the high pitched sound. After that, wait another second, and dash+slide forward. During the slide (after the spawner has already appeared) tap LMB for shotgun daggers and that should kill it without spawning any skulls.
https://youtu.be/aBSDX5z-pJU

Now, you have a few seconds until the snakes and scuttlers spawn. You should start rocket jumping in the direction of the snakes, and try to position yourself above their heads. Start holding RMB to prepare for grabbing their gems as lasers, and do the stomp as soon as they spawn. The first times you'll probably miss and just stun them, which is fine (just aim carefully and kill the entire snake pack with 1 shotgun shot), but the ideal outcome is to squash them and kill them instantly, as soon as they spawn. You should try to get used to squashing snakes, specially during the blue/gold upgrades, since you can use the upgrade as bait and stomp the snakes while they go towards the upgrade beam.
https://youtu.be/KcDTll8UnWE

Now that the snakes are dead and you stored the 3 gems as a laser shot, do a ricochet shot to stun the scuttlers, and kill them with a 3 dash+slide combo while you hold RMB.
https://youtu.be/RaJ4egDSspU

As soon as you deal with the scuttlers, go towards the spider, and when it spawns go under it and do a ricochet shot to instakill it (again, hold RMB afterwards to store its gems for a laser shot).
Remember you can do the spider ricochet in 2 ways: while sliding under it, or while jumping under it. There isn't a better choice, it's just situational and depends mostly on the enemy spawns.
Let's say you killed the scuttlers and the spider is very far away: you should do a dash+slide first, and release spacebar early to transition the slide into a jump, and then start bunnyhopping after that until you reach the spider. When you do, just do the ricochet shot under it (it doesn't matter if you're starting or ending a jump as long as you keep the bhopping speed). Alternatively, you can do the spider ricochet while sliding, which is best to kill spiders at mid distance.
https://youtu.be/jcwT4Ki3BQU

Now that the spider is dead, look for the spawner and kill it with ricochet as soon as it spawns. Remember: killing spawners quickly is extremely important, since the game is waay harder with the skulls floating around.
https://youtu.be/RZKXaWdmFYw

Now that the 2nd spawner is dead, you need to start adapting to the spawns. There won't be a "good" kill order since it'll mostly depend on the enemy spawns. That being said, it's a good practice to try to repeat the previous kill order as long as the spawns allow you to. If you see that the next enemy from the kill order is too far away, just kill whatever's closest to you and start improvising.

If you want to keep repeating the same kill order over and over again, you definitely need to learn gemdashing (the fastest way to kill scuttlers). Every time you want to kill a scuttler pack that's about to spawn, try to get kinda close to it while holding a big gem, but not too close or the gem will break. When you see they're about to spawn, jump with the big gem in hand, and press LMB+W+SPACE in the direction of the nearest scuttler, without letting go of RMB. Holding RMB while gemdashing gives you a little slowmo effect which is very useful, since you need to be very precise. After that, just dash (without sliding) towards the other 2 scuttlers. This is probably the hardest mechanic to get used to in the game, so don't get frustrated if you don't get it instantly, it'll take a while. But it's also the best mechanic to speed up your early game.
https://youtu.be/GFmvy0a-hBI

So, at least until the first scuttler gemdash combo, your early should look kinda like this.
https://youtu.be/RimJCSUkPjk

If you weren't unlucky with the spawns and you were able to keep up with the spawns (killing everything as soon as it spawns), you should have a pretty clear arena when the blue upgrade spawns.

If there's a snake pack and scuttler pack, use the upgrade beam as bait and squash the snakes while holding RMB. Then do a ricochet+dash combo to the scuttlers.
https://youtu.be/R7MC_gtHJMk

There may be slight variations to which enemies are up when the blue upgrade spawns, but if you are going fast enough, there should be 2 spawners coming up at the same time, with some other snakes/scuttlers and a spider coming up too. When the 2 spawners are about to appear, rocket jump high enough to dash into one of their gems, and then dash towards the other spawner's gem. After this, look straight up to do a gemdash that'll take you extremely high. Now you should grab the upgrade while holding RMB, and after that do a stomp in the most crowded area possible. With most enemies stunned around you, the best thing you can do is to grab a bomb with LMB and let go of RMB to explode it in your hand. Exploding a bomb with a decently charged laser will do a giant explosion that repeats many times, so its extremely useful for killing scuttlers instantly, instead of just stunning them (like when using normal homing shots).
https://youtu.be/muvtcK1uOgs

If there aren't any bombs around after the stomp and there's just a big gem, it's a bit trickier but you should just rail it (without grabbing it) and try to kill everything as fast as possible, as seen in this clip.

During all of this, the centipede will appear, but you should deal with it after you've cleared the entire arena. Now you have 3 choices: you can save the centipede head for a stormrail (way too complicated), break the centi head and use its gems for a homing attack (railing a big gem), or break the centi head and use the gems normally to start chaining ricochet kills. I'd suggest the latter since it's the most consistent one, for me at least.

If you do that, you should now have a huge laser ready and a lot of enemies about to spawn at once. Like i said previously, fresh spawners are a number 1 priority, so it should be your first kill. But there's an exception to this: if you see that a spider will spawn in front of a spawner, you should first ricochet kill the spider (jumping into it, not dashing), and then ricochet kill the spawner quickly, before it spawns skulls. If the spider isn't close to the spawner, or its too far away from you, just kill the spawner first, break the big gem, and ricochet kill the spider. After this, just kill whatever's closest to you as fast as you can, while never letting spawners gush any skulls. If you want any directions, you can use this clip as reference. The most important thing is that you should use the gold upgrade to rail a laser, kill a bunch of scuttlers and then use their gems for another homing attack. More on this in the Homing Loop section.
https://youtu.be/TQYbI4OCI1M

Now you're on your own. Just try to keep chaining ricochet kills as quickly as you can until the boss spawns.

My pb:
https://youtu.be/ot0CbZ0-22Y

That's all. I'm probably missing some things or getting some other things wrong, so feel free to send suggestions on the comments. Also, if you have any questions or just want some advice feel free to add me on steam too.
Good luck with those runs!