So I cleared the game. To my knowledge I am the first one to do so since the start of the rating period.
Which I believe is a bad sign, but I have feedback.

As it is, the game's extremely unforgiving, sending Medicine at the start of the map after a single hit...
I just cannot keep count of how many times I had to go through halls that I emptied, once again, for 3 minutes, just to die near-instantly to a leap of faith into the Super Laser Room™.
There's no encouragement from the game to keep the players going. I cannot realistically believe that anyone would actually want to continue playing after 5 minutes.

May I make some suggestions, one or several combined would feel a welcome addition:
- include a checkpoint system: this allows players to not feel like they've lost all of their progress
- give a health system to Medicine: this gives room for mistakes, so that players can actually make some progress each time they catch up to their furthest progress.
- make Medicine able to defend herself better: I really like that the poison can erase bullets but Medi can't quite rely on attacks to defend herself. The spray covers only the front and has a very low rate of use (or a long cooldown). The bubble seems to be an anti-air but it's as much (if not more) awkward to use for defence.
--- In a way it's kinda similar to classic Castlevania games, where attacks are kinda "rigid" and can cancel enemy bullets too (I'd compare the spray to the whip, and the bubble to the Axe subweapon). But in order to be proper defence tools, the attacks do need to feel and be faster. Being fast doesn't make the whip and Axe feel less "rigid" to use but it does make these responsive enough to fend off attacks.
--- You can also improve Medi's attacks. You could make Medi able to continuously spray poison by holding O and also aiming the spray with WASD.  With that, you could have the bubble be launched in a much smaller arc so that Medi can easily blow into it, or deal better with enemies below. Then the aimed spray launches the bubble in the same direction, and that would look golden.
- calm down with the enemies:
--- Biggest offender was the leap of faith into the Super Laser Room™. On multiple "walk backs", I just land into a fairy without being able to make progress. If you ask me why I don't dodge it, well it's because I can't react before it's too late. Feels quite unfair and super punishing for it.
--- Seriously calm down with the amount of enemies. Work them smarter, not harder. Having a whole army of enemies in a room is not bad by itself (it can be good for spectacle), but it's bad when every time you attempt to get in the room, they somewhat make it harder/impossible because they can move and they moved into *these* spots.
There's also the fact that there are some situations where Medi just cannot deal with - thinking about the first Yinyang ambush  where they come from both sides, and the sides are closed off by fairies with spiral danmaku. How do *you*, the dev, not die in this part?

Other notes:

- Medicine can randomly die in the vertical part with LOTS of Yinyang orbs.
- There isn't much actual use for the Slow mode, is there?
- Medicine's attacks are so rad. They also cancel bullets, awesome!

tldr: not enough power to the player...

To all my fallen comrades who gave up trying to reach the end, I show you my playthrough.