Knightro Slime tank in Challenge mode:
To unlock the Knightro tank in Challenge mode, go inside the church and press Y, L(2), Y, R(2), Y, Up, Down, Select.
The Nemesis Slime in Challenge mode:
To unlock The Nemesis tank in Challenge mode, go inside the church and press Y, R(2), Up, L(2), L, Y, Down(3), Y, Select.
Giggles in Tank Masters mode:
To unlock Giggles in Tank Masters mode, beat the game, then talk to “Meggan”, the green Egg Slime in the northwest building of the central part of town.
Gott Schliemen in Tank Masters mode:
To unlock Gott Schliemen in Tank Masters mode, defeat the final Boss and rescue all 100 Slimes. Then, defeat Hooly and the Shogun in the last round of Tank Masters mode.
Schwarzen in Tank Masters mode:
To unlock Schwarzen in Tank Masters mode, defeat the final Boss. Then, go to where you defeated Slival on Mt. Krakatroda. Defeat Slival again.
Don Clawleone strategy:
First, kill your tank. This may seem counter-productive, but killing your tank makes winning a lot quicker. Once your tank is dead, Don Clawleone will attempt to infiltrate your tank to get to the engine. He has only two attacks, both of which take time to execute, so you can kill him easily. One releases a ring of fire that moves too fast to dodge, while the other makes a shockwave of energy that also moves fast but only in one direction. Once he?s dead, the tank will say that this does not change anything, but it actually does. Until he is resurrected, his tank will not shoot, allowing plenty of time for you and Slival to fire rapidly. Once his tank dies, run towards it and Slival will follow. Don?t worry about Don Clawleone destroying your tank, even when he teleports to you and tries to kill you. Ignore him since Slival will try to kill him and break the energy rods in your way. He is good at this since he can break many at once. Once you reach the engine, which resembles a Kaffrizzle item, Slival will try to destroy it but fail. You will still have to do it. After that, the tank will explode and you will win. He also has drill-like items that prevent you from using your cannons and Kaffrizzles, which release a group of fireballs that can damage you.