This game looks super cool and controls really nicely, well done! I have just a few tiny complaints! Mostly small and easy to fix clarity stuff and I think the game would be way more understandable. I actually liked a lot of what other people mentioned as problems! Alright to start, in the first level I had no idea what the cubes did and I had no idea where the key went. Could easily put a key icon or a giant lock on the door and that would help out. The cubes could use a little bit of integrated tutorialization. For example, if the first level is a single hallway with a key and a door at the end of it but you die before you can reach it, and there's a small offshoot where you can touch a cube to refresh the decay, then you've fixed both the key and cube confusion! It also wouldn't hurt to put a small heal graphic or something else for the cube, so long as you can integrate it into your artstyle well enough. As for no crosshair, that seems alright to me so long as the bullet has enough explosion radius, you're usually shooting the ground anyways. This type of game might better benefit from ADS instead of a crosshair (if shooting enemies precisely becomes core further than I made it) I only made it to the thin bridge over lava (quit because I got annoyed at the movement, lol) BUT! I don't think the movement was the problem, I think the thin platforms were the problem. Slippery movement can feel really good so long as you're not expected to make precise movements, and gaining momentum in this felt awesome. So I honestly think giving more large rooms with long hallways and jumps to clear with momentum could be a better direction to go with this. Great job though! You've got the visual style and clear vision and direction, keep it up :)