Just an excellent arcade shooter. Its so much fun. I'll lose a few hours to this game just rampaging through the hordes of Satan's army. One of the last true classic arcade shooters that is well deserving of your money.
It is short, yes, but it is priced low to match. It is even more stylish than the original campaign and engages your attention much better than the original game. Compared to other games in the genre, this is a real treat.