Mr. Do! was originally released by Taito as an arcade game in December 1982. It was then ported to many video games systems and home computers including the Atari 2600, Atari 8-bit computers, Colecovision, Commodore 64, MSX and Apple II.
Mr. Do! is a circus clown (for whatever reason!) and the main object of the game is to dig tunnels in order to collect cherries. If he collects 8 cherries in a row then a 500 point bonus is given. There are also red monsters (sort of like dinosaurs?) to deal with and one way to dispose of them is to dig under the apples at the right moment to let them crush a monster!
Other similar 80's games were Dig Dug and Boulderdash.
The video at the top of the page compares twelve different versions of the game, starting with the arcade version. There's even a version for the Sharp X68000, a computer that was only ever released in Japan.