Excellent game for two players! I spent an entire summer in grade school over at my friend Brian's house. We played the hell out of this game where I piloted the legs of the mech while he operated the turret. It took team work to win that game be we eventually made it to the end. If you have kids you want to teach team work, this game will help them bond.
Not sure, wait until they get to the ice level. When Player A fires the guns it pushes them backwards on the ice. That makes it really hard for the second player to control the legs.
P.S. Single player with the SNES controls was terrible. Trying to move one way while shooting the turret another way was impossible. If converted to modern dual joysticks it will probably work.