Hamster Ball
16 Achievements
PS3
Guinea Pig
Complete all non-bonus levels in Hustle Mode.
12.0%
How to unlock the Guinea Pig achievement in Hamster Ball - Definitive Guide
This isn't hard. All you need to do is to complete all levels in Hustle Mode, which will will take roughly 90 mins of gameplay. The hardest levels for me were the gravity levels. There are 33 total levels (don't know if that includes practice levels).