I would have said similar things with Game Dav. The art is great, and you have implemented it beautifully in this game, which reading from your information might be one of your first, so extra well done! The effects, the wall climb and double jump were superbly implemented with fluid in motion makes this a great submission.
What I found very punishing was your decision to place such a hard obstacle first. The wavy "poison grass?" that coats the first steps, could be mistaken for actual, "step-on-me grass", so I died there a few times before realising what happened. Then, I am required to hang on a wall and then jump over, something uncommonly found in platformers, thus (I at least) kept dying 10+ times before I realised what was possible with the toolset you have given me.
My suggestion would be to try and bring the difficulty scale down a lot, and build baby steps. Some games here on this jam do a great job with this, I am sure looking around will help you reflect if this is your aim.
You have done something amazing here! Please don't keep it locked behind such a steep difficulty spike.