The sheer scope of this one. Lordy lord. Very impressive.
The game has a good diversity of abilities/armour enhancments, as well as a ludicrously sprawling map - very much in the spirit of Metroid. The menu & ability to Save/Load is a nice touch.
Given the amount of features and level work that's gone in, it's hard to fault the slightly clunky elements of moment to moment gameplay - but I do think that given more development this would be the area I'd like to see given a slick polish. The ideas are all there and implemented well enough, but there are occasional hiccups and moments that cause frustration when a double-jump doesn't pop properly, etc.
Really great job overall :)