One of the earlier robot fighters, Metal Clash is a stylish and simple hunk of fun where you get to punch and kick in any direction while you scroll left or right through colorful backgrounds.
You've got two buttons to go along with the joystick, punch and kick. You use the joystick to fly in any direction that you want and you can aim your attack by pointing the joystick. In fact, it is particularly well animated when you punch or kick up or down - (your fist or foot thrusting upward from your robot body).
The enemies are mostly robots but some UFOs and other crap and come in varying degrees of difficulty. Some take many hits. The fun of the game is definitely the flying in & out, up & down to punch or kick a rival and then flying away quickly (no, I'm not a coward). This "stick and move" style of boxing takes on an extra dimension (pun intended) because you are flying - zoom up quickly from underneath, kick the enemy, and then zoom to the next guy - that kind of thing.
There are a few power-ups in the form of weapons. And while they aren't all very powerful, they actually change the dynamics of the game significantly. Now, you can stay away from the enemy and shoot him. Imagine when mankind first invented guns and they were fighting guys with knives. All the weapons quickly run out of ammo and disappear.
Your life is tied to an energy bar at the top left, take hits and it diminishes, don't let it empty out or it's curtains.
Metal Clash is from 1985 so the graphics are simple but well drawn, the best part being the robot parts that go flying when one is vanquished.
It's easy to get into and simple to control. The fighting and flying is very satisfying. I could imagine the game with a different "skin" and it would be a good Superman game.