Kinda dissapointing, as a I wanna be the guy kind of games enjoyer, I must say it need to be polished a bit more, the hitboxes on the red obstacles are kinda misplaced on some levels, specially in level 2-5, here, you normally could stick to the front wall so you can slide and have big space to maneuver, but instead you get killed instantly, my recomendation is to move the obstacle a little to the right so Marisa doesn't die here that easily.
That said there's another thing that could make this game less frustrating, that instead of a shot, she could get proppelled and hover on the opposite direction of the mouse, if the impulse is very short you could still keep the difficulty, but the shot gets a lot of misdirection on air, depends strictly on the mouse speed and that is very hard to control if you need a click on the specific right direction, that could ease things a little bit for the player.
And another thing, it could be nice that you couldn't backtrack on the rooms, since a couple of times I unporpusedly clicked and got reeeeally back a couple of rooms by accident.
But hey, don't feel bad about it, this really took me back to the time where flash games really started to take off and people were just discovering how things worked, those kind of people worked very hard and made awesome games eventually, so don't lose hope, you got the spirit, and the world is always in need of games that break the spirit and challenge the mind : 9