To beat Congazuma, the first boss. Stay off the ground and get on the pegs and climb right, the boss should appear. Go back a little and and charge up, then ram into Congazuma's head. You can only hurt his head. DO NOT try to hit him again as he is red and touching him loses you a heart. Repeat this 3 more times and Congazuma's history! Remember ONLY hit his head, it's the only way to cause damage!
At the title screen, press L, A, B and up at the same time to enter a cheat code screen. Enter the following codes to get the events:
65942922 - Attack Battle 3
55860327 - Climbing Race 5
35805225 - Obstacle Race 4