TwoDots is simple, yet challenging (pictures)

This addictive sequel to Dots is fun, playful and hard enough to keep you playing. The game has almost 200 levels, all grouped in themed worlds that have their own obstacles to keep you on your toes.

Each level has a clear objective, such as clearing out a specific number of colored dots or obstacles.

Each level has a unique configuration of dots and it's your job to connect two or more of the same colored dots to clear from the field. The longer chain of dots you connect, the more points you earn.

Connect a square of same-colored dots to clear that entire color from the field. In  some levels, you need to create squares to win, so get in the habit of creating a square as often as you can.

When you're out of moves and don't complete your objective, you lose a life in the game. You get five lives to beat as many levels as you can. Once you run out of lives, you need to wait 20 minutes for each live to regenerate, or you can pay 99 cents for a new life.

If you beat a level, you advance to the next and get a score for your efforts. There's a star rating, too. If you connect your Facebook account to the game, you can see your friends' scores and earn medals for the three highest scores.

Once you get past the beginning world, nearly every level has at least one obstacle to get in your way. Here, in the current last level of the game, there are several obstacles, such as blocks and fire dots.

Every day you get a new quest in TwoDots, usually to clear out a certain number of obstacles. Finish the quest and you'll get supply crates that contain power-ups to help you in tricky levels.