Doodle Blast has you drawing lines to get the marbles down to the jar. Sometimes you have to draw ramps, other times you have to draw walls, and sometimes you have to entirely re-route the marble or marbles in an elaborate route to the jar. You have a certain amount of time to do this and you can restart if you don't like what you've drawn or you fail the level. Once you're done drawing with the limited amount of ink you have, press start to see the marbles drop! If your ramps and walls worked, you'll get everything in the jar. If not, try again - there are so many levels to run through!