I bought this game in a very discounted by PSN. I glad I did this. I had two days of the office and this is the kind of game to be played if only have a couple of hours. I beat this game in only 9 hours, which is good for an old school game with no major story.
But it is fun enough to put you in 4 hours straight of gaming without wanting to stop. This game is not grate but it is fun, it is fast, it has a lot of good explosions, good enemies (no brainier at all). It is not Walfestain, it is not DOOM. But it is well developed with good graphics and good physics considering this is not AAA game. I do not even know about it existence.
I recommend to play this game if you want to spend a weekend at home and has limited budget. This game is only $4.99 and has a lot of fun in it. Do not expect any story-line, nor a robust character. Only expect good weapers, dozen of enemies and a short experience.
12 levels, very short each. No more than 30 minutes each. Good value for your money.