Having lost their parents in a plane crash, Mike and Lisa try to persevere through their broken childhood. The boy still wonders about the bottomless cave he was warned away from, though, and one day curiosity gets the better of him. Mike wanders into the darkness alone, seeking adventure and closure.

This action-platformer tasks players with solving each of 10 stages' puzzles and secrets to reach the end. It uses simple arcade-style controls and mechanics, akin to early-'80s classics such as Pitfall II and Tower of Druaga. Kill more creatures than required and you might get the "bad" ending; satisfy just each level's conditions to reach the "good" one and play the game's second loop. Mike's Lonely Journey saw release on the short-lived FM-77AV platform, with an FM-7 port having fewer levels and downgraded presentation. Oh! FM Magazine distributed and produced the game, while its developers soon moved on to companies like Namco and Tengen.