Get your facts right, boy. L4D1 was never a great game. The whole thing got old after a 3 weeks for me. Yet, the demo, which is only two maps, has not gotten old yet and its been about a week. Thats how much content they got piled on. L4D1 never got good reviews from legit sites, and all of them commented on how it felt incomplete and repetitive. How on EARTH is L4D2 a ripoff? Do you know the definition of ripoff? A ripoff is something which is over priced, which L4D is not. 45 bucks for L4D2, while most games are about 60 bucks. And it is definitely not a ripoff in the sense it was stolen. L4D2 is basically filling in what they missed out in L4D1, and adding more onto it.
Have you even played the demo? I thought not. Anyway, the demo is free for public use now. Download it and play it, although the demo is 360 port due to the PC demo files being lost at valve. It has glitches galore due to this, but by god does it rock. I am sure your (very)very young mind shall be changed.