Rush Bros is a hardcore platformer taking after the likes of Super Meat Boy, but fails to understand any aspect of why people enjoy these type of games. Precise controls, level consistency, and a feeling of fairness all elude this game and that makes it impossible recommend.
The game's gimmick is that parts of the level move with the beat of the current music track playing. It's an interesting idea but one that shouldn't have gone past the prototyping phrase, where it should have been discovered how badly it works out in practice. This includes traps and not every object responds to every beat, which when mixed together with the sub-par beat detection makes this movement almost impossible to accurately predict. This also causes certain songs to make certain levels ridiculously hard, if not impossible. A few of the later levels take this mechanic to such extremes, I firmly believe that they are some of the worst levels ever included in any game.
The other main issue with the level design is invisible traps. Pretty much every level has spikes, but some of them in some levels will shoot at you when you get close. There's no way to tell which ones will do this. Spikes will even shoot at you from off screen with no warning. What this unfortunately results in is rather than skill-based platforming, you simply have to memorize the levels to do well. That's not real difficulty, it's poor design.
These problems combined with sloppy controls can make this game very frustrating and it's not hard to see why over 90% of the reviews are negative. While I did enjoy the music the game has to offer, it would be better to save your sanity and pass on this one.