Should be the 2nd sentence on the game page and also described in the "how does this game fit the theme" on the submission/rating page. But I maybe I should describe it in game, or what?
I was mostly thinking about players who download it and play later without the game page open. It is a very fun concept that I would love to see as a full-length game.
Ah yes. I'm very likely expanding this and thinking about making it a puzzle platformer. Each level would have a few "sublevels" that you change between (like the current switching level mechanic). I would then make the switching of sublevels into an action in the game and not in the UI.