You might wanna rent it if you don't wanna put too much effort into the different storylines. It's about 8-10 hours long, but with all the different endings (I've read there's 22 endings) you can go back and change some stuff that you did and get a different outcome. So if you just wanna play it and beat the game, just rent it. If you want to explore all the possibilities, you might as well buy it.