Based on the demo, so far it's just more L4D. I doubt it's going to make any new converts and a fair few people are going to cry foul at having to pay for something that does feel like a large update rather than a new game. For some reason the sound quality seems to have take a big dip as well, whether that's just the demo I don't know, but the sound is noticeably softer and less sharp than in L4D.
Having said that it's really run with with the bigger/more theme, even in the demo the extra weapons made a real difference to the gameplay. The new infected mix it up quite effectively as well, the jockey and Charger completely buggered up my team that's well rehearsed in dealing with Tank/Smoker/Hunter/Boomer, that's good, Spitter, not so much. The rolling crescendo event is genius too.
Compared to what EA/Actibliz come up with in annual sequels it seems to be a much better value effort. I think for £25 it's worth it, but like L4D I wouldn't have paid full retail (£50) for it. If it turns out to be massive then I'll stand corrected.
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