You need to be careful about the rap vocals (especially Flowny's verse), they're not piercing through the mix enough. They need to be balanced way louder, or you need to duck the other instruments, especially if the backing track is going to be this sonically complex during their verses.
Also,
knowing the song where that Lulz verse originally came from, try moving the acapella so it comes in about a half-beat later than this. It'll make more sense flow-wise if you do.
If you want to end the song unresolved, doing it with the fourth of the root isn't the best way. Try the fifth; authentic cadences more common than Plagal cadences (I think?), and the tension will be more palpable. Or, you can just move that synth perfect fourth down to a major third interval so it resolves with the strings.
I think you could switch out a couple of instrument choices, particularly drums, but that's really up to you. Nothing pops out at me as offensive.