Wow! Nice game. It is so simple, but so good, and the concept is so original.
I feel that it can benefit from some sound effects though. It would be good to have some sounds when you change the selected ring and for acomplishing and failing the objective.

This one is cool, but tough. Even on the normal difficulty I had a hard time getting them all lined up in time.

I really enjoyed this. The mechanic is cleverly simple

This game makes excellent use of the 20 second constraint. Really good job.

I really like the game mechanic. It's super simple, challenging without being difficult to play and rewarding to beat. I think that with some extra variations on the mechanic, this game could be expanded into a full game. It would probably also work well on mobile if you figure out how to let the player easily switch rings.

Great job

Very cool concept, I like that a lot.