GamersGate is offering the Aliens: Colonial Marines + Season Pass Bundle
for 80% off (10€). The base game has been heavily discounted before, but not the season pass AFAIR. I can't tell whether the game is really as bad as the reviewers said (haven't played it myself yet), but at this price point, it might be worth the risk?
Assuming this as a question: gameplay mechanics and atmoshpere are good but the pitfall are the Aliens AI , the scripting (sometimes Aliens just sitting there waiting to be shot and such things) and bad texturing, ocassionally missing completely (though not in so important places like vent shafts). But there are some fucking scary moments in there. In the end it's enjoyable, actually and there are much worse FPS out there. I'd say if you can enjoy Duke Nukem Forever you can enjoy this, too.
Wether you want to support the politics and Aliens canon treatment surrounding this release, is a completely different story.
Season Pass: get you mostly Mulitplayer Stuff, which is kinda dead. Bughunt DLC which is fun and also available for solo gameplay and Stasis Interrupted solo-mission that lingers on the threshold of "so bad it's good" and "just bad". So IF you are interested in the add. stuff get it in the package since it's def. not worth €7.50 on it's own. If you just want to satisfy you curiosity, the €5 main game is totally sufficiant.
For the €8 I paid on GMG for A:CM+SP I am ok, I spent money worse. At least I am not regretting the time I put into it, like with some other games (RF2, DX:IW, Mafia...).
my 2 cents ;)