Excellent Game. Each level introduces new designs/ different mechanics that keep the Game Fresh & Alive throughout the Entire Campaign. My "Half-Star" Off has to do mostly w difficulty progression. I am familiar w similar games & really coasted through at least half the game - maybe even 2/3. The difficulty rises in small steps for the latter, but I found myself confronted w some peaks in the last 1/3 of the Game, which didn't comfortably slow down my coasting, but put me at a dead halt. This happened at least 3 Times, and the levels weren't back-2-back. Just some Peaks & Valleys in the latter 3rd of the Game, really. Otherwise, the Level Design differences level-2-level were enough to keep me hooked the whole time.
The other part of the "Half-Star" Off has to do w want of an "Undo" Button. I really wanted to hold down the left-click on the mouse and run my course through the Hex-Puzzles, but I found myself clicking one space at a time BC of accidentally moving off course & consequently failing. Would love to see an Update that adds Replay Value via new Modes and/or Leaderboards. But w/ or w/o the latter: Again, Awesome Logic Puzzler that gives the brain a consistent workout! ~ DoctorThrift