Awesome game! I really enjoyed the level layout and the combat felt solid. This is a really fun spin on Metroid escape sequences. The presentation and feel are overall very awesome.
The one thing I'd note is, the dithering in the underground is a bit hard on my eyes, especially when the screen is shaking.
Seriously awesome stuff.
Np at all! If level design is new to you you did a knockout job of it, as it's quite involving. I'm impressed.
Regarding the dithering, if you're taking suggestions I'd personally do away with it in favour of a palette order inversion when above ground vs when underground so that every sprite looks like it's being strongly shaded by the sun. It's an old trick that still looks quite clean, though I don't know how it'd work with 3 + 1 highlight colour vs 4 shades of the same colour.
