To b or not to b

I am a Chinese independent game developer. This game is based on my game called "bdpq" two years ago which was featured in "Challenge Your Brain" by App Store.

HOW TO PLAY

1. Convert the four letters "bdpq" to each other by sliding up, down, left, and right.
2. Change all letters to the same letter with one line, for example, let them all to b.
3. To bdpq is EXTREMELY DIFFICULT so we called it the God Mode. Maybe this is the real form of this game.

Designed by Sleeeeepfly Studios