There are other things that you have to figure out for yourself. Like how the blue squares merge. And how they will try to box you in.
I still can't figure out why the orange square turns red temporarily and what the significance is. The folks at Greenery have a web page - all in Korean - but not contact info.
I can't stop playing it. I make my moves too quickly. This game is a winner.
My high score is 1074. Sagar is #1 with 5555 and John Paurillo is #2 with 4996. #3 has 2596.
Update 5/23/17: Two things. First, I can't stop playing this game. I'm going to have to delete it. Second, one of my students found a glitch in the program and is now the top scorer with 5614. I'm tempted to do the same, but I just can't.