Looking forward to the full release! Ditto all the great things that others are saying about the atmosphere and quality of the puzzles.
-Two quality-of-life updates that would be nice to have are a move counter in the corner and an undo-move button (!)
-The 'high' (optimal) move number has occasionally changed on me, but I'm not sure this is a bug. On a fresh game, the 'high' for level 1-1 is 23 moves. I've somehow achieved a 22 and cannot recreate it and the current 'high' is now set at 22. Maybe holding down the arrow keys to move instead of individual inputs can mess up the counting?
-A move counter would help illustrate the move cost of some things that aren't intuitive. Burrowing down + back up (1 or 2 moves?) Moving into a fuel tank and getting pushed back out (1 or 2?) Getting out of your robot and jumping back in (1 or 2?) etc.
-The countdown to self-destruct is not the best for impatient people like me. Getting out of your mech and self-destructing does this immediately.
-Tip for others. If you collect the gem, you don't need to complete the level for it to show up in the level select, but sometimes it doesn't register immediately after leaving the level.