After completing the first 5 levels in Crash Bandicoot 2 you will end up facing 'Ripper Roo'. Ripper Roo is a kangaroo like creature that hops around on a platform. Each square that Ripper Roo bounces on turns into a block of TNT and all you have to do is dodge them and wait in the gap were he hasn't placed any TNT and then he will blow himself up. After that you cannot hit him but he will do the same thing again but with nitro blocks after you have dodged them he will blow himself up then you can spin him. After he has done that 3 times he will die and you will win the level.