I finally got round to playing it after charging through my backlog of games.
It's damn fun. Just slithering around and admiring the writhing sprites is satisfying by itself. Does have a metroid feel what with the accumulation of powers and such. Once you have a few powers you can choose different ways to violently murder the poor hoomans. Good god the violence. My only major gripe is that there's no ingame map and it's easy to get lost. Apart from that, highly recommended. This game deserves more attention.