I think you did really well, don’t sell yourself short.
There are multiple different levels, and most come with a new gimmick. I love that there is a custom close-up death animation for every hazard; that’s a great touch!
The game doesn't go on needlessly long, and even ends with a narrated boss battle.
The running animation could probably be a bit better; it doesn’t look very natural.
Collision detection is also the reason I almost quit the game – the cyan level requires very precise jumps over spikes, yet the hitboxes of either you or the spikes are too large, so I was constantly getting unfairly killed from touching the “invisible border”, not the spikes themselves. Even when you stand still, your legs don't always touch the ground.
Overall, if the hitbox happens to be a rectangle, it doesn’t have to be all around the sprite; often, it’s better for player experience to make it a bit smaller (so you can overlap a tiny bit without being killed).
I was wondering what you’re going to find atop the building, the reveal didn’t disappoint. Although you should’ve told Bob it’s a great experience, and he should go as well (for making you go in the first place).