I likes it.
I'm stingy on my pianos sadly soundfonts are not the greatest for quality. I also have a tendency to love pianos with a good strong reverb on them. The dryness of your piano takes away from the overall mix for me. Anyway I'll do this the easier way and go by times.
Intro - Offbeat bass hurray. I'm sure you could do a little better. The plucky synthe's delay could use more feedback to give a wider feeling. The reverb on it doesn't seem to be too strong either (if any).
0:28 - Piano enters and eh not a fan of it I hear some reverb but not the strong saturated sound I have in mind. Plucky synthe still kind of takes over the overall mix.
1:00 - Percussion has wowed me but overall it's fine. You keep interest with the transitional style sounds which is awesome good job on that.
1:30 You have a new lead it seems I like this one with the pad behind it. The plucky synthe comes back in still in need of better delay (in my opinion).
2:15 Not sure what this new synthe is but it widens up the mix a bit. Arp in the background is good not too loud or too quiet just the right amount. Your bass is still offbeat and the mid to high end range is losing in the fight for the mix. Your bass sounds filtered because of it's lack of higher frequencies, try layering more then one bass some at different octaves.
2:40 The piano is brought back in, this time it fits a little better since the mix has more going on then before.
3:15 Synthe breakdown/lead?
3:40 Back to where we started, not much to say an outro is an outro.
The things I liked outweighed the things I didn't which is hard now n' days to find that among newgrounds. Try to work on your bass it's interesting but it's not a "how can I achieve that" kind of bass. Try layering since and working with longer delays.
Everything is just my opinion as is everyone's review so don't take anything to heart. I tend to review songs I like anyway.