I really enjoyed this one- it's a really nice little puzzler that I picked up very quickly. In general, I found the interface very clear, but I occasionally got confused in some levels because I wasn't quite sure which way a turtle would turn (clockwise or anti-clockwise). It can be deduced but in some levels where turtle movement is a bit more hectic I tended to get confused. A visual indicator for this would be very helpful.
Besides that it has a lot of potential. I can think of a few things to add to the list that may make good game play additions
- Variations in turtle speed and timing would add a temporal dimension to puzzles
- Suspension tiles, that keep a turtle stationary for a certain amount of time.
- Other means of the player interacting with turtles- this may be variation in the kinds of blocks you can put down or something more radical
- A play on the color mechanic: possibly ways of changing a turtle's color to impact how they behave or what tiles affect them
Having puzzles that operate using the dynamic elements of the game could lead to some really challenging puzzles- the ones I enjoyed the most were puzzles where I could use the other turtles in the solution, and would love to see more mechanics exploit this feature.
But that all depends on what direction you want to take it. In all regards a fun game. Thank you for sharing!