The first generation is how it was originally, in the original thread. You can find an example in the original thread (which is linked on Page 1 of this thread). Rolls were extremely complex. There was ammo, and you had to return to the ammo dump when you ran out, and buy more when the dump ran out. Perks were all general, and anyone could get them. Guns had a range beyond which they would start to lose accuracy. There were artillery barrages that you could buy. It was basically about the same as the game was a few days ago, except the rolls were more complicated and they were hidden. You couldn't say "okay, he has 3 HP left, I'll take him down", you had to guess at it. Some people like that, though.
Second generation is when I modified it. Rolls became vastly simpler to GM. I cut a lot of the interesting and creative but complicated parts out. It was a bit unbalanced. During this stage I added a lot more enemies, instead of just having two.
Third generation is now. I've added blasphemous amounts of weapons. They have been balanced, except for this one thing but that doesn't really matter once you get higher power. There are many new levels of weapons, not just two kinds of pistols but five, not two kind of sub-machine guns that are basically the same but four different ones that are really quite different. Where there used to be two medical items, now there are seven; medics have been buffed up so the class is finally useful and adds an interesting layer to the game. There will be a lot more enemies, and I hope that the players will be extremely diverse. That's already happened, in fact - we have RAM the Brute/Acrobat, yourself, Joscar, the shottyman, some footsoldiers with Uzis, Red with his sniper rifle, and Zchris the sadly underpowered demoman (working on buffing up that class). We will soon have RNG the Hero, Rolan the Medic, and Allstone - whatever he is, he's so rich he'll surely excel at it. I love it very much. I hope to perfect it and make it into a game that is easy to GM but fun to play.