"->" should be a valid answer for level 25. This reminds me of another game where you see the shape slide through a line - more visual, but more complicated images. Can't remember what it's called though
To solve the Extra-Hard Upstairs Puzzle, all you have to do is blow a smoke ring, then walk into it to push it along. You don't get anything for it, though, "other than that tingly feeling of success and a statistics API call" that earns you the badge.
I like how each special gummy is based on a different skill: timing, accuracy, reaction time, etc. What I DON'T like is how going above the clouds with pants on fire does absolutely nothing besides drain you flame meter.
Fun fact: In the credits, it says "All characters appearing in this work are fictitious. Any resemblance to real persons, living, dead, Styglek, Loki, or Creeper infested is purely coincidental."
In addition to OneLeggedRhino's idea, I also think this game would be nice if there was an animation for the stone-laying. Having them appear instantly makes it a bit harder to predict visually.
 "Deeper Sleep"){kind=icon}
 "PicTune"){kind=icon}
 "Fixation"){kind=icon}
 "Burrito Bison Revenge"){kind=icon}
 "Yu-Gi-Oh! BAM"){kind=icon}
 "Creeper World 2: Academy"){kind=icon}
 "A Duck Has An Adventure"){kind=icon}
 "Reverse Boots"){kind=icon}
 "Grey"){kind=icon}
 "Blob's Story"){kind=icon}
 "The Trader of Stories"){kind=icon}
 "Everybody Edits"){kind=icon}
 "You Have To Burn The Rope"){kind=icon}
 "The Crystal Temple"){kind=icon}
 "ELEPHANT RAVE"){kind=icon}
 "Focus"){kind=icon}
 "Steppin' Stones"){kind=icon}