Good first start! Gives me SotN vibes almost. Setting the vertical camera limit will help a lot and hide the gray space above the level. Some acceleration and friction might be a good addition but it's not a huge deal. However having to press down again to uncrouch is weird, you should uncrouch when you let go of down. Also it's weird not having any air attack Give the player some i-frames after they get hit or give the enemies a cooldown timer though, it's easy for an enemy to attack you right after you get up. Keep at it though, with some more polish and original assets this could be something great!