I love the S&P series with a passion because despite the drug induced stories the games have, there is a strange sense of satisfaction when you kill anything that moves or has an attack. Star Successor is beautiful by the way, it's insanely addicting, and the prequel is just as awesome. The end of stage 6 where you need to rescue Kachi from the crane in Star Successor is, I swear, one of the hardest damn things ever in a game IMO.
I even wrote a review of the first game.
Give it a read. 
It's written a little weirdly now that I read it again, but it gets my point across.