It could have been much more. The first half before the 'get drunk to survive' plot thread comes into play feels awfully rote, as although the actors do well with their character troupes, the creature-feature element is nothing intriguing or unique. Once the drinks pour, it gets funner, yet it isn't enough to sustain the narrative with just the gimmick. There's still some cute jokes, but they're not funny enough.
Immensly enjoyable genre flick. Makes up for a not too original screenplay with many laughs and some genuinely tense moments. And it has the all time greatest Aliens reference. Well worth checking out at the cinema, it's one of those films that works best with a group.