Sounds like you were having fun with this - not a bad thing, but I didnt feel there was a massive amount of structure. I liked the varied synths that were introduced throughout, but for a 4.15 song, it felt a bit long due to a lack of clear breakdowns - it all sort of felt like there was a constant loud reverb masking each element and every new sound introduced just built on the same melody throughout. Only when it hit 3.25 did I feel like there was some sort of actual change for a little bit. Would have been nice to have some sort of melodic interlude in the middle that introduces the new synths etc in a second half. The Piano could have had more built upon - like a solo piece, pads/arps (as an example) if you will; which would establish the core theme more until the build brings in a drop of sorts.
The mix itself was ok, but a lot of the it felt too centralized, not giving other elements their own breathing space (the piano for example was very quiet and overshadowed after the start, and just sounded like someone was just enthusiastically pressing keys with no reverb). It can be dull mastering, but practice more EQ on each instrument to make them standout more, try panning and compression...especially to make the drums a little punchier as they also felt like they were just there to keep the pace in the back, and were not varied or built upon.
I am not an expert critique and have done so from my point of view, so I hope I articulated myself well :) I absolutely get this was experimental, and I could hear a decent song that would suit a very progressive video/level design.