Conceptually great, in practice, needs something
Loved the concept, the style, the voice acting, the writing, and the level design.
However, there were a TON of glitches, and as a few people have said, the code wasn't especially optimized. Get those things fixed, and keep adding new things
The run until you die aspect is fun, but the game is just the right length for that mechanic, much longer and I would have stopped out of boredom. I could see the game being extended indefinitely, where each cure delivers a new side effect that you have to utilize until THAT gets cured and delivers a new side effect and so on.
Also, I'm a big fan of extra content, and I think I found everything, even though that's when most of the glitches happened. This included random dying to nothing, 2 music tracks playing at once, being unable to move left or right, etc.
Summary: a little extra work, this game could easily be up there with the best.