If you don’t know what type of film Piranha 3D is simply based on the title, then there’s no helping you. It’s interested in a few things and doing those things extremely well: being over-the-top, fun, and bloody in all senses of the word. The kills Alexandre Aja puts on-screen makes its R-rating seen mind boggling. Aja doesn’t pull his punches (similar to his previous films), but here the difference is in going more for pure fun rather than bleak horror. This is no soft R. It pushes the envelope.