Double Teaming
When you have two players, make sure you act like two. Take two different attack points, or even set up each other's attacks on the boss. Don't stand right on top of each other, or else it will be only as good as one turtle.

Jump Kick
Try jump kicking an enemy from the opposite side of the screen. Once there, jump kick to the other side, then back, and so on. You'll find that you can destroy a ninja without getting hurt this way. Put two ninjas on opposite sides of the screen, and you will have the advantage!

Special Attack
Practice hitting A+B before you get very far. If you can press them both at the exact same time, your turtle will use an attack worth two normal hits. This is great for clumps of ninjas. Try a special attack on a boss when you are double teaming on it.

Submissions and rebuttals should be e-mailed to nintendofanssite@yahoo.com. Proper credit will be given, and please tell me if you don't want your e-mail revealed on the site.