There are a few levels that are difficult to complete with a 3-star rank. One of these, is level 4-1, "Suprise". Start by killing the crab, then return to the starting position in the middle of the right side. Build a path very close to the lava. Enter the lava to kill yourself. After respawning, immediately go through the lava and return to form a rectangle while you are invulnerable. Next, work your way safely to the left side of the screen while remaining in the middle position. Cut it when most of your enemies are in smaller section. Then, complete the rest of the level quickly when safe to do so. Note: If you are having difficulty getting a three-star rank in a level, try the hard difficulty setting. The difficulty factor will double your points.