The progression of it gets kinda boring after a while. There's really no change of mood through the whole thing. The sounds are good, but I'm guessing some of them are presets? If I'm right on that, try to stay away from presets entirely. The outro is pretty weak too, it could be a lot better. You're right on the mixing too, it needs work. The drums drown a lot of it out, but hey, at least you sidechained! Also, you might want to add some kind of bass or pads or something in the back, to fill some space. It feels kind of empty during some portions as it is.
It also seems a bit cliche, don't you think? The vocal splice you chose is a bit overused, and it feels like this idea in general is just incredibly overused. Think about it, Pinkie Pie, party, that vocal sample, etc. It just feels generic, so it's not really going to catch anyone's eye.
My main suggestion would be to spend some more time learning essentials; stuff like sound design, music theory, mixing, and stuff like that. Once you nail those, you'll really start to see your music improve.
Hope I helped!
