The glitching effect made well, artstyle is also good and leveldesign is interesting sometimes. Everything else is either average either bad. Especially hitboxes and swimming mechanic. Hitboxes should be a lot smaller even a 3-4 pixel touch equals death. Swimming mechanic is also not good. Looks like you just erased ground checking mechanic and made gravity a bit smaller. You should at least give player ability to hold W to swim, not just spamming it. Also sounddesign is poorly made. At first I really disliked the jump sound and incredibly high volume without any access to lower it. Also it's actually like only 3 sounds: jump, water jump? and death, you should at least add some water sounds when you jump to it, walk sounds and maybe some music. The art here is interesting but I cant say it's actually something special because of its simplicity
Well everything was made from scratch, so good work, I think