[j1mmie]

There was a game called Specter Spelunker Shrinks that required arbitrary shrinking and growing. It's more of a prototype than a full game, but I could imagine this exact mechanic working in a more fleshed out setting.

A cool thing about the game is that time also scales with size. So the challenge provided by moving objects also scales with the character's size (sometimes beneficially, sometimes not).

https://www.youtube.com/watch?v=NZ65SWBb1Kg