I don't think one can make the time limit stretch forever?Edit
Figured I could write it, just in case: Doing nothing at all, will unfortunately(?) not make the microgame last forever. Doing nothing for approximately 15 seconds, will make the skies get gradually darker. Once it begins to get darker, I got the personal impression that once it begins to get darker, it will get much faster darker from that point on, no matter how quickly the skies can be made brighter again by how the rainbow is drawn on or the bucket is filled. I'd estimate a mathematically theoretical limit of around 13-14 minutes, but not ∞.
The preceding unsigned comment was added by DandelionSprout (talk).