Whoa, this is awesome!
I love how much you used the sine lead. It really gives the soundtrack a cheerful whistle-y feel, without being too whimsical for the darker tracks. I especially liked the Space Kraken theme, between the 12/8 time and the rock organ.
I do agree with the previous comment that it sometimes feels derivative of its inspirations, but it was at least original enough that I wasn't picturing Kirby or Pokemon as I listened.