Attack enemies when they are moving from floor to floor : When enemies are moving from floor to floor is a great opportunity to attack them! Attack them when they have landed!
More points with jump kicks : You get 200 points if you take out an enemy. If you do so with a jump kick, you get 500 points! Take multiple enemies out at once and you get more points.
Push bosses out of the screen : If you attack a boss and push him out of the screen, you can send him to the other side of the screen.
Bring back the iron ball : After shooting an iron ball, press the control pad in the opposide direction to bring it back.
You can pick up iron balls : If the time limit comes when you have an iron ball, the iron ball turns back to Ball 1 and flies away. Make use of this and press the kick button right before the time limit. The iron ball you have kicked turns back to Ball 1 at an ideal position and you can pick it up.
Go for the green enemy : There are a bunch of enemies carrying items. Take them out and obtain all those items.
Jump at heights : You incur damage if you get to a height difference while walking. If you jump and go down, you take no damage.