Great start, but could be better
First off, I love the Bunnykill series, finally getting a chance to play a game that features the same kind of characters is something I've been waiting for. Truthfully, I really hope people start making more Bunnykill games and movies. I'm really bored to death of the Madness ones.
The graphics and backgrounds were pretty good, and the characters definitely did seem very close to the ones from Bunnykill. From the moment the game started, I could tell it was a button masher, which is fine but I felt there was room for more as I progressed from level to level.
One thing I did notice is that I was taking damage from enemies on the top platform even though I was on the bottom, and logically, their swords never should have been able to reach me. At first, I didn't even notice it, but later on, it got to be annoying. I noticed the enemies on the top and the ones on the bottom didn't switch levels like you could, but I think it would be better if they could rather than be able to damage you in ways that realistically shouldn't be possible. As for the enemies themselves, I'd mix them all together, rather than have enemy A with the red swords come first, and then enemy B come with blue swords come around once all of enemy A was gone. Have them all fight alongside each other with different weapons, it would make a lot more variance. Meanwhile, the boss fights were good, I'd definitely keep those.
Also, the music could have been better. Most of it was just "white noise" as someone else described, and I would have liked to hear a more action-oriented loop that would have fueled the action and intensity a bit more.
Also, I would have liked to see some more weapons, and possible item/upgrade powerups that would have made the game more interesting and varied. Stuff that could have upgraded the weapons, give you entirely different weapons of more power, bestow special abilities or attacks, or even make the gas cloud bigger or upgraded would have been really nice to see. In addition to that, all of the levels were pretty much the same except for the backgrounds, which were nice but it still made the game very linear and feel like the same thing over and over again. Adding obstacles/hazards to overcome, things you can destroy to get out of your way, item crates to pick up powerups from, all of these kinds of things would give the game a really great gameplay boost and would make it a lot better.
Still, keep up the good work, we need more Bunnykill tributes like these.