Simple 1500 Series vol.066 - The Kaiten - Mawasun Da!! is a collection of a lot of wacky mini games with a difficult control method since in most of the games the player has to turn quickly the left analog stick to gain speed and is really hard to do it.

The main character of the game is a wacky alien that will be used in most of the mini games of the game. The mini games are really different since there are golf, fishing, flying, baseball, destroy a robot, arkanoid, unroll dresses, skateboard, cooking and serve, etc.

There are 2 main game modes:
- Competition: Play 5 different mini games and try to win as much points as you can.
- Free play mode: Practice all the different mini games.

The game features also a 2 players vs mode.