All cheats for this game by platform: SNES
Stage 1 Boss, and all midstage bosses of the same type: When he tries to jump-kick you, roll ([B]) under him, then jump ([A]) and attack ([X]) when he tries to spin his metal bars at you. Then, use a combo ([X] repeatedly), and knock him over.
Stage 2 Boss, and all midstage bosses of the same type: Dash and attack ([X]), or dash and Special Attack ([Y]), to get close enough to use a combo ([X] repeatedly).
Stage 3 Boss: When he charges at you, roll ([B]) under him, and jump ([A]) over him when he jumps and slides at you. When he gets up, use a combo ([X] repeatedly).
Stage 4 Boss 1: Start by blasting ([L] or [R], then [X]) him off the screen. Wait until he gets on the screen, then roll ([B]) under his first jump and fireball shot. Then use a combo ([X] repeatedly) to knock him back off the screen again.
Stage 4 Boss 2: Jump ([A]) and attack ([X]) to get close enough to him, then use a combo ([X] repeatedly).
Stage 5 Boss 1, First Form: Roll ([B]) frequently. If that does not get you anywhere, dash and special attack ([Y]), then use a combo ([X] repeatedly).
Stage 5 Boss 1, Second Form: As he is charging at you, use a special attack ([Y]) and roll ([B]) some more. Do not attempt a combo.
Stage 5 Boss 1, Third Form: Use all your blasts ([L] or [R], then [X]), then roll ([B]) and use special attacks ([Y]). Do not attempt a combo.
Stage 5 Boss 2: Roll under him when he attempts any kind of attack, then jump ([A]) and attack ([X]), followed by a combo ([X] repeatedly).
Stage 5 Boss 3: Simply stand under him and attack ([X]). He will eventually fall, and the floating balls will not hurt you.