In Virus Laboratory you have two different modes of play: Endless mode or Puzzle mode. In Endless mode, you have different colored blocks that you can only get rid of in teams of three or more. The bottom fills up with blocks and each row that forms pushes up the pile on top. Your goal is to not let the blocks get stuck at the top. In puzzle mode you have to take a pile of blocks and figure out what is the best order for eliminating them so you don't get stuck with single blocks at the end. All in all Virus Laboratory is addictive with two styles of play and many levels!