You are a clown who moves around a maze. You can dig new paths to avoid monsters and collect cherries. Kill monsters with a ‘powerball’ or drop apples on them. Kill them all or eat all the cherries to go up a level.
The object is to clear each level of cherries and/or monsters. The monsters may be killed by hitting them with your powerball which bounces through the paths, taking unpredictable directions at junctions or dropping an apple onto them. The level is also over if you complete the EXTRA box or collect the diamond which appears very infrequently ‘Special’, awards an extra credit.
You can dig extra paths through the solid parts of the maze in whatever shape you like. The apples will be found dotted around the screen in the solid parts. To construct traps for monsters, it is important to dig just under them so they fall into the path behind Mr. Do., then turn around and push the apple back to a path which turns downward, preferably just over the edge, and you have a trap! Wait for a monster or a few to appear in the path below, and push! If the monsters wait too long under the apple, they can become ‘diggers’ and dig away at the maze towards you! Sometimes they go under the apple and squash themselves. An improvement is if two apples can be lined up, so you are protected against a ‘digger’.
The central target, where the monsters appear from, may be collected once all the monsters have appeared. This is noticed by it becoming a ‘prize’, e.g. ice cream, biscuits, etc.. When you collect the prize, the Alphamonster and his four henchmen appear. The Alphamonster may be in the EXTRA box at the top or moving around the screen. The Alphamonster and his henchmen cannot easily be crushed under apples because they usually eat them! They can be killed individually with the powerball or, if the Alphamonster is killed, all the henchmen turn into apples.
After every three levels there is an intermission where a tune is played and a larger more detailed animated picture of Mr. Do and the monsters is shown. The time to complete each level and the method monsters, cherries, EXTRA or Diamond is shown. The paths in the first level resemble a ‘D’, after this each level is laid out as the digit, i.e. ‘2’, ‘3’, ‘4’ etc., up to ‘0’ for level 10.