i've done other games before (basically, wait for user input type of game) but i want one where things happen all at once (things moving, as well as the player moving). i figure this would be the best way in figuring out how to make a larger scale game. now here where you guys come in. i need an idea whats easy to do. also, i'd like ot be able to read up on it too (maybe a site that has theories about designing the game)

my main problems with game design is #1, things happening at the the same time (enemies moving around) and #2 collision detection. so please people, post up some ideas, and if u have them, sites that teach the theory about that game design (i remember seeing/reading one about pong)