Aside from things looking more plain at the start of the game, visually your game looked cool. The sliding mechanic felt cool, especially when using it to jump across a gap.
I would have really liked SFX or at least just ambient looping audio to give me something to listen too. More hit FX, even just a white flash would have been nice. Swimming felt a bit jank, with the swimming animation and underwater attack animation, but being able to go underwater was still pretty cool.
I got a black screen after entering an area with poison, so I'm not sure how much more content there was after that, but from the opening rigged boss, and the toad/lizard thing boss, I can say the boss fights were creative.
Nice entry.