Totally worth checking out
The weapons are great, even though it's the standard loadout of weapons nowadays they're strangly all fun to use in this game. The game is pretty cheap to buy too. I picked this up for $30 (Canadian) at Bestbuy about 3 months ago.
If you're into Sci-Fi shooters you have to get this game!
The aliens look great and are a blast to kill (no pun intended). Plus there's a lot of different Mechs to climb into and use. They all handle pretty well and you can swap out the weapons on most of them. The Boss battles are excellent too and fairly memorable.
The one thing I didn't like is that fact that you really can run through the level most of the time without killing anything (if you wanted to). If you do that you're pretty much wasting your money though. KILL STUFF.
For the cheap price it's worth a buy. The levels are fun enough that you'll come back and play it again every now and then even after you've beat it.