It's very good for a first game. The game plays well, music is a solid choice and the meta-commentary was really good.
There is an area in the tutorial where you can get stuck in a pit that is too deep to jump out of it which forced me to restart so I wouldn't call it the safest platformer. And the precise jumping on level 4 and the pit full of 1 long 'objective' kind of went against the relative safety of the previous levels. Level 4 in general kind of goes against the theme as there's only one real route which is the right one.
It's a cool idea that the obvious and telegraphed route isn't at first the win condition. For improvements probably look into coyote-time to make your platforming a bit better.