Got the bad end - I didn't even know there were momentos to collect.
It's difficult for me to untangle criticism of the game specifically and me just not really liking the platforming genre as a whole, but I was glad of the tonne of spawn points, since it felt like I would Meat-boy esque die over and over. I think this style of platforming design to me is reminiscent of the "Nintendo Hard" genre where you have to learn puzzles by running headlong into problems over and over and only making progress by memorising stuff you couldn't see when you start moving, which is an issue. I can't count the number of times I said 'fuuuuuuuck' under my breath, and not really in a good way.
I think I struggled with the KB+M controls a lot, especially kicking off a wall. There was a lot of times I just felt like Camilla wasn't doing what I wanted to do, whether that was because the physics was strange (I had a lot of trouble with the golden wind segment; sometimes she would resist the wind a little, sometimes she would just get blasted straight back to the left) or she would wallkick when I didn't mean to. I think hitting the direction key into the wall felt very strange, except maybe for the narrow walljump bits; if I want to jump away from the wall, my mind defaults to wanting to use the dir key away from the wall, not into it. This could be like coyote time or other platforming things where some frame buffering trickery is needed to make the platforming feel good; I'm certainly no expert in that regard.
As others have mentioned, I think the hitboxes might have been a big large on obstacles (they likely fit the sprite exactly) - what you end up with is a lot of dying before the sprite is seen to hit the obstacle (probably due to speed of sprite movement), so it doesn't feel good. I think a lot of games use hitboxes smaller than the visual object for this reason. The circular saws in particular I think suffered from this issue.
The only other real criticism I have is that Keygirl's weapon thing was often a very similar colour to the background, so every once in a while I'd get offed by a spinning blur I couldn't see. It was also possible to die while respawning, which was funny but not really much of an issue.
All of that aside, I still think it was a pretty good package all around. The sheer amount of content, art, level design etc generated in a month is so impressive to me. I think more could be done with the animation to make it feel more lively (the attack animation in particular feels a bit stiff) but considering the time constraints (and how annoying animation is to get to look natural when put all together) it's still quite cool. And so many magical girls!