Snake Rattle 'n' Roll

Snake Rattle 'n' Roll features two snakes - Rattle and Roll - as they make their way through 11 isometric levels. The object in each level is to eat enough "Nibbley Pibbleys" - small round creatures found throughout each level - to gain enough weight to ring a bell on top of a weighing machine located at the end of the level; this causes a door for the next level to open. (Wikipedia)