Pretty good.
The gameplay loop works well and the use of dead enemies as a staircase to reach the top is a good use of the jam theme, though simple.
The upgrade shop for increasing your health and weapons is a nice addition and also ties into the theme as each time you die you have to upgrade yourself to get further.
CFH needs some instructions on how to play as I had to guess I moved with WASD at the start.
The controls and physics work well enough, although sometimes I seemed to get blocked or was failing to jump when trying to jump up the dead enemy platforms causing me to fall down.
The pistol and shotgun can get tiring to use, especially since the demons become more bullet sponge-y as the game goes on meaning you have to click far more often with those guns which tires your finger out and it's worse when the screen is filling up with bullet sponges.
There should also be some indication of how far you're climbing as I didn't know I was near the end until I reached it.
The art is suitable although somewhat amateur and the sound effects are pretty good.
Generally the game is enjoyable, although it can definitely be improved with better art, some music, different enemy types and more upgrade/weapon options as well as making it so you don't have to click constantly for some of the guns to be more effective.