>>716245505 (OP)AvP 1 - campaign is complete dogshit, horrible balance, maze-like levels, awful FMVs for the story, sometimes doesn't even tell you what the next objective is, I would skip it
AvP2 - campaign is awesome, well thought out, you see a realistic Weyland Yutani facility from multiple different viewpoints, better gameplay, better story, better everything
AvP2 Expansion - Some good story, awful maps, worth a try