Dragon Unit (known as Castle of Dragon internationally) is a beat'Em up and platformer developed by Athena Corporation and published by SETA (in North America) and Athena Corporation (in Japan). A NES version of the same name was published. but it has a different story and different gameplay.

You play a young king (or two kings in 2-player co-op) who needs to rescue the princess of Wenlary from the claws of the dragon Zuriv.

You can slash with your weapon and jump. Additionally, there are two paths: one in the foreground and one in the background. Unless there are obstacles or pits, you can switch paths any time. There are several weapons in the game which either appear from smashing things or just lie around. They differ in hit ratio, reach, damage and speed. If you die, you get set back to the stand weapon. You have health bar, but loosing health is also indicated by loosing armour. You can find a new armour to get back health. There is also a time limit, and the time can be increased by collecting hour glasses. Finally, there is an item which grants invincibility for a short time.