This video shows the gameplay of Diamond Mike on the Atari ST. In 1986, I ported the game from the 2068 computer to the Atari ST computer. The graphics are a little better on the Atari ST.
Some of the later levels not shown here are more visually interesting and more complicated. It is not clear if the person showing the game fully understands how to play the game. It appears as if he doesn't.
The demo appears to be running on an Atari ST emulator.