I really enjoyed this game when I first played it on my very own PS2 back in 2008. The game is really great as it not only contains fascinated graphics, gameplay but also awesome sci-fi weapons such as lightning (proton blaster), fire katana. The storyline is also good. For me, the BGM's are awesome. They are really composed gracefully with an immense touch of futuristic scientific atmosphere... This is an underrated game.
Furthermore, as the classic Contra games, this game also has badass aliens in the form of bosses/sub bosses.