I've looked at the patch notes and messed around with some of the new items, but a HUGE change to note for this guide is that Halo no longer blocks projectile damage, only physical hits from making contact with an enemy. Given that the whole point of this is preventing enemies from reaching you with the Chainbelt, Halos are basically useless for this build.

I've also gone through and updated this guide to reflect any changes broadly. I also just, like, developed a better understanding of the game, so I've removed a couple upgrade items that were previously considered necessary. The skill loadout didn't really change with the update, but I tweaked it a little bit and added a blue circle at the origin point so it's a little more comprehensible.

I also have just started to look into the different skins (is that what we're calling them?), so I haven't factored them in here. If there are any game changers I'll list them once I have a chance to look at them more, and I'll do the same once I manage to unlock the rest of the new items, but I wanted to make sure this guide got updated as soon as possible once I realized the Halo had changed.

How about those new loop bosses, btw? I'm loving them so far!

Welcome! Grab a snack and stay for a while.

The general idea of this build is to turn your whole screen into a lethal area for enemies. It relies on the Chainbelt for lethality and the Injection to turn your screen into a danger zone. The Chainbelt is unique, as it only needs a few things to shine, and once it starts to shine it really does it all! As a result, we really only need a couple items to hold us over until that happens. You can slot in whatever else you prefer, and you can still rest easy knowing you're able to do something else while Cyl and her belt deal with everything!

Note: This build is based on per-frame damage. I've observed while using it that playing on 2x speed that your per-frame damage is effectively halved, as the enemies are traveling twice as far per frame and your per-frame damage is not changed to compensate for the 2x speed. This build can manage 2x speed for a while, but you might need to add things on if you're getting into really high mortalities (it used to be around mortality 70 for me, but with performance increases from the new update I'm not sure anymore. Contaminated Picayune has been kicking me in places I didn't know were possible lmao, but I'll test this to failure once I get past her!)

Let's start with the skill loadout and settings configuration! I'll show you the skills I think are important to making this build work, in the order I think that they're most important. Feel free to skip this part if you've found skills you're comfortable with.

Gaining XP is very important. Most of these skills serve to increase the amount of XP you get, and attracting all XP after boss death makes sure that you don't leave any behind. Drawing lines to pickups follows the same line of thought to ensure you don't miss anything useful.


The extra increases in HP help with survivability, especially after the halo nerf, and slowing the game speed while sneaking helps, especially if you're planning on looping and taking on the new bosses! Rerolls and bans are nice to get the build off of the ground, but if you're short on points you can get away with skipping these.


Drills are nice boons after every boss, and definitely worth grabbing. I tend to prioritize crit chance with these, but extra black holes are also good. Really, you can grab whatever you find yourself needing in the moment!


These last ones will help with bosses! As far as I can tell, the -20% HP on bosses is actually 20%, in the way you or I might use it and not in the way that the game uses % to represent HP typically. Plus, an extra 10% damage on enemies with status effects can really pull some weight!


If you have any overdrive levels, you should have some extra points to spend. I like the new fish stock stuff (I think it's funny) but bosses dropping black holes is also nice. Spend them how you'd like!


As the game progresses, you should turn down your weapon visibility. The screen can get very clogged, and depending on what other items you might take it can get unbearably clogged. As an example:

You might notice that there are only 5-6 crucial parts to this build. When I first made this guide, there were a couple more, but the more I thought about it the fewer upgrades were necessary. Frankly, this isn't really a build so much as it is recognizing the Chainbelt and nurturing it to leave it's comfort zone as a close range support and watching it evolve into a "go get a glass of water" machine. By no means do I want to take credit for "discovering the strength of the chainbelt" or anything, because I definitely didn't! But the Chainbelt is The People's Upgrade, and I want to do my part in spreading the word about its usefulness.

Because this build is easily capable of carrying your run using half of your max items, it's great for getting unlocks done! You can slot in whatever item you need to equip 8 of and know that you can still finish your run, or you can integrate it into whatever other items you like to run easily!


The Chainbelt is definitely the MVP of this build. This will be how we maintain lethality for non-boss enemies for the bulk of your runs. This is an upgrade that you should be consistantly upgrading throughout your run.

The Injection is the glue that holds this build together. This is crucial to upgrade early on. I would keep it as high priority as the Chainbelt until you've reached a Chainbelt size you're comfortable with. However, at that point it becomes less important to upgrade. Eventually, you want to extend your Chainbelt off screen by a decent amount to deal with any projectile-shooting enemies before they get a chance to approach enough to actually shoot (they don't seem to shoot off screen).

Getting some sort of elemental status on stronger targets is important, but which one(s) you go for it up to preference. Poison (via the Hunter's Bow or Mask of Plague) lasts the longest, and Stun (via the Electric Eel or Plasma Lamp) is super useful for bosses that move a lot, since it forces them to stay in the Chainbelt zone for longer. Adding the Element Crystal is always a good move too. But, the most important thing is having any status on bosses to take advantage of that nice 10% damage buff.

The Halo used to be the choice for survivability I recommended for this build, but after the new update (yay!) they no longer work for projectile damage. Frankly, they were super good, so the nerf was probably deserved lol. Friendship ended with halos, IV bags are my new best friend!

The Eye2 is included to give both hitscan for bosses and "discretionary" damage to help with particularly dense groups or particularly strong enemies. It's important to upgrade while your Chainbelt is in its early stages, but after that it becomes decreasingly important.

Full disclaimer, I haven't unlocked all of the upgrades added in the Contamination update yet. I will update this if I find any others that help the build.

Extra XP is always nice! Granted, it's a low numerical increase, but it can add up. Plus, it gets lonely out there, and having a face that's not trying to kill you for once is nice!

I like the Angel Wings because they help keep distance between you and the enemies in the early stages when that's necessary. However, you don't need very many, and they matter very little once your Chainbelt is established.

The Chainsword can be helpful early on, and unless I'm misunderstanding its stats it seems to ramp up particularly well the more you put into it. Since it benefits from the Injection too, it is a nice fit!

If you really want to lean into the "helicopter" part, throwing on slime spikes is super simple, and adding the soul spear and/or dagger glove would be on theme too.

Hopefully this information can be helpful to you! Feel free to mold this to your personal preference, and enjoy the easy of leaving your computer running while Cyl does all of the hard work. Do note, however, that with the new update the XP is auto-collected after the boss dies, which means you cannot count on a level up to pause the game before the boss fight! Also, shoutout to my brother for introducing me to this game, I have loved every moment of it!