You can usually take your time with puzzle games, but Bit Bit Blocks is anything but leisurely. You have to play this puzzle game at lightning speed to have any hope of winning. By making bigger blocks, you can beat back your opponent's advances, and that opponent can be the computer or your friend/enemy.
Your grid of anthropomorphic blocks at the bottom of the screen is mirrored by a similar grid at the top of the screen. You have to drag the blocks around to make larger blocks of four or more matching colors. When you merge blocks, you can tap them to shoot the block up to your opponent's side. Those blocks you send over are also locked for a few seconds, complicating matters for your opponent. This pushes the divider closer to them as well. When the divider hits the goal, you win. Your opponent is, of course, trying to do the same thing to you.
The first few levels in single-player mode are fairly simple, but after that it's suddenly very important how efficiently you can move blocks around the board. If you can't build a new attack block every few seconds, you're going to be outmaneuvered fairly quickly. That's just the single-player mode, though. Two players can complete on a single device in Bit Bit Blocks. You each take up residence at one end of the device and start matching blocks, just like in the single-player mode. This works best on a larger phone or tablet, obviously, but it's a neat take on multiplayer.
Bit Bit Blocks is free to try with a limited number of lives, after which you need to recharge by watching ads. Simply pay $2.99 and the life system and the ads are gone.