So I downloaded this today and...
Developers of Metroidvania games need to learn that an active soundtrack is an important part for making these games more interesting. The game tries to get by with a minimalist more ambient soundtrack and it's not cutting it. With the way the trailers were shown, I wasn't expecting them to go this route. Outland also had this problem as well and I quickly grew bored of the game because of it. I don't care how good your art is (and it's really good here), but when your just flying through tunnels it's the music that makes the atmosphere for these games. With Shadow Planet (and Outland), it feels like the game is sort of this dull drag inbetween set pieces because you're just moving through halls that look marginally different in near silence. Every other good Metroidvania game since Metroid more or less avoided this problem by having some good music around you that made the world seem alive beyond your narrow range of vision. The developers of Aquaria understood this and the game came out infinitely better for having a great soundtrack.
The game is fun enough, but this dullness is dragging my progress down. I've barely touched it and am having a hard time moving forward because of it.