I really like the repeating harmonic part; it almost serves as the percussion section for the first minute or so.

That change at :51 was unexpected. I really like the arpeggiated part, especially the melody that repeats at the end of the progression each time.

Around 2:50, it starts getting repetitive; you need to either shorten the song, or write more parts.

The part at 3:55 was a really cool change.

C4C? Links are in my sig.