So... monsters attack your Knight in rows and your job is to heal each of the Knight's limbs before it gets critical. Luckily the monsters show which limb they are about to attack above their heads so you can prepare.
The hard part isn't keeping the knight alive, but keeping your torch lit! You start off with 4 torches and can find/craft more as you progress but it will still be a struggle. Most of your "Quest Failed" messages are probably going to be from a burnt out torch.

The good news is after losing over and over again will you earn points for meta game upgrades that improve your game permanently!

Most of your time will be spent clicking on Discipline (the spell with a stairs icon) to increase the EXP bonus, and clicking on Mercy (the star icon) to restore health of a limb. Left click on Mercy and then click on a limb to restore, right click to stop healing and do other things.

Use your mouse wheel to move a little targeting circle that picks which monster you want the Knight to attack. It's a good idea to attack monsters frst that have an item or torch behind them. Also, the Knight will never move the circle without you... even if the column is empty! So keep moving the circle to select the target.

After enough attacks the Brave meter will fill and the Knights next strike will hit everyone on the front row.

Once your EXP bar is full you both gain a level! The Knight gains max HP and the Healer gains max MP. There's also an upgrade to restore HP and MP on level up... which is crucial.

Leveling up also gets the Healer a skill point to either unlock a new spell or upgrade current spells.
I highly recommend going for "Protection" as your first spell since it gives one limb a shield for some time. "Faith" is also very useful since it spends 40 mana to generate a random mana potion, and 2/3 of those mana potions are going to restore more than 40 MP.

During the Day the knight will regenerate HP on all limbs, and during the night the healer will regenerate a lot more MP. Day/Night cycle is shown with a sun or moon on the left side of your screen.

• Keep spamming Discipline while you can! Try and keep the EXP boost as high as possible to make each kill count, especially after you get the upgrade to gain HP and MP on level-ups.
  
  
• When your torch is low, craft potions and burn them as fuel (click the little "x" on the bottom right of each item). Some items burn for longer.
  
  
• You can only hold 5 torches at a time so don't try and pick another one up!
  
  
• Use "Protection" on a limb when you see 3 or more monsters about to attack it. It'll save you some mana from healing it. Also if you see a really strong enemy about to attack it.
  
  
• Using a Red Stone kills all monsters from the current tier - BUT ALSO DESTROYS THE ITEMS ON THE GROUND! Don't be like me, don't waste a Red Stone only to destroy the torch that was one line away.
  
  
• Every tier has one torch and one Red Stone, so it's safe to use the Stone right after you grab the torch.
  
  
• Keep playing! Upgrades make the game so much more manageable, especially the ones involving torches.