There isn't a difference between the red and cyan bombs because right now they do the same thing. Maybe in the future you could make some bombs that give powerup, or destroy more blocks, like make it has a 3x3 explosion, or have a cross explosion, or something...? And the game doesn't really speak chain or reaction to me. It just a simple win/lose condition...?
I think the leaderboard is the most stand out feature in this game. Overall I think this game did pretty good.