It's great game. The main issue for me is that it gets bigger but not more difficult with levels. + Action was confusing at first but once you get it it becomes the game-breaking rule.
All you have to do:
- Use 1 or 2 + rule to eliminate loads of strays
- Use + or 1 distance to get plenty of first confirmed "kills"
- Finish the rest
I would loop right arrow key as well (go back to the begining if trying to access past last page). I would highlight more a single match in a pair as simply making a icon bigger wasn't enough for me.
I love that it's like more visual and interactive sudoku.