Stone Man's stage is pretty simple, with the only real challenge coming from the area with the platforms which rotate and move rapidly, and then fall. Apart from this, it's pretty straightforward (and the challenge of those is greatly alleviated by use of Rush and the Super Arrow.)
There are some hidden areas in the stage, which are found by shooting the bottom right-hand corner wall of some rooms, including the first big rock wall you'll come to after the first major ladder section. You'll find the Beat letter in here, some weapon energy in a similar room about halfway through the stage, and a Mega Tank in one near the end of the level. Whenever you're in an area with a rocky wall, shoot the bottom right-hand corner wall so that you can find these areas.
Stone Man isn't too much of a challenge, but there are some moments that will frustrate you. He attacks by jumping around the room, activating a rotating stone weapon as he does so. When he lands from a jump he'll collapse into a mass of bricks, and he can't be harmed during this time. He's weak to the Napalm Bomb. Hit him while he's standing around, perfectly vulnerable. When he does a jump, lay a bomb right where he'll land. He'll take damage when he lands on the bomb, right before becoming invulnerable.