This is one of the few games that I'm shocked to find was made just in the 48 hours given. Really well done systems design, visuals, art, and sounds. The controls felt pretty smooth, and the aesthetics were really well done. That said, my main problem with this game is its lack of instructions.
Without watching the trailer video, or looking at the description, I had no idea what I needed to press or do (other than the obvious WASD and space). The easiest way to circumvent this is a text, either in the world or on the HUD, that tells the player what button they need to press. Crouching a lot of players will likely know, but not everyone, so even in that area it's good to communicate to the player what they need to do when they get to that area. And for new abilities that haven't really been done in other games, you definitely want to add something to let the player know what they need to do.
Overall, again, really good game, it's seemingly just that lack of communication is missing.