Yeah, it's always better to understand why you need the plugin, frankly if you don't know why you need a plugin, then you won't just start using it automatically - it has to provide something that you need. It might sound counter productive, but it is really best to know the ins and outs, the problems, even if that means making mistakes, or spending time with techniques that won't do the job. You need to figure out how your collision system has to work based on past games and experiments, then hopefully by then Box2D will tick all the boxes. I like 2D physics games, so I got it just for those - but it could certainly deal with a platform game, allowing physics, taking care of collision, swinging ropes, vehicles. It's got all you could need but figure out what you definitely need first.