I don't think I'll consider momentum because at it's core this is a shoot'em up, not a platformer. Maybe I should categorize it as an STG and not as an action game.
about candles: You are right, I should not suppose a player knows anything (in this case about castlevania).
About pets: yep I really need to add some better tutorial.
I'm glad unity didn't shit the bed for linux, and thanks for playing.