Well bottom line flash is used to make all the games on AG and other mini-game sites alike. It's not like there is a tower-defense-game making program. Its more like there is a game-making program and its Adobe Flash.
I know very little about making games, but i wanted to learn, so i came up with game maker, is it any good? From what I've learned, it seems very useful and has the ability to make all sorts of games.