The best replacement for chipmunk is squirrel.

The best alternatives to chipmunk are rated as following:
★★★★★  squirrel
★★★★  ground squirrel
★★★  box2d
★★★  gopher
★  mouse droppings
★  red squirrel
★  chinchilla
★  mole
★  striped gopher
★  vole
★  lowkey
★  cricket
  griminal
  sugar glider
  cricket .22
  ground squirrels
  cricket 22
  tinchy stryder
  degu
  woodchuck
  mouse poop
  angry german kid
  icekid
  flying squirrel
  maxsta
  prairie dog
  star wars kid

Your alternative for chipmunk is not listed? Suggest!
Speaking about chipmunk, one probably shouldn't forget about cocos2d.

Other search terms related to chipmunk and their ratings are:
★★★★★ cocos2d
You have in mind a companion for chipmunk and it is not yet here? Propose!



Google Trends

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chipmunk
squirrel
ground squirrel