The core game is the same but it's more fleshed out. I played the Flash version myself and decided to buy it, as I liked it a lot. The atmosphere is great and I like the simplicity of the game.

Each time I failed I'd be able to use the experience to devise better strategies for survival in the next game. The end-game can be punishingly difficult and I've had a few goes where it's felt like a stalemate develops, but from what I've read the devs are taking comments on board and hopefully it'll get more balanced. I'm going to press on and see if I can actually beat it, but it's far from perfect.

I think that the three reviews currently on GOG are perfectly vaild, so I suggest reading them and making an informed decision.

I still really like it though and am certainly glad I bought it. It's pleasing to hear that they are planning to bring free updates to the game as well.

Very much so. In no particular order:

There is an endgame(Kill all enemy gates) rather than endless survival, builders are their own class separate from farmers, build catapults, graphics and sound are much improved, costs have gone right up meaning there is an actual economy to manage, farms are buildings now, a single hit doesn't send someone right down to 'wildman'(Just to unarmed peasant), people don't come to your camps; you have to go to them and back, garrisonable towers, buffs for your archers and walls, enemies come in four varieties rather than two.