Complete level 4 of the indicated training game to unlock the corresponding new training game.

Training game	How to unlock
Alien Attack	Complete Meat Defender level 4.
Avalanche	Complete Zoo Feeder level 4.
Count Mania	Complete Avalanche level 4.
Court Curling	Complete Pot Shot level 4.
Drum Topple	Complete Alien Attack level 4.
Meat Defender	Complete Pirate Wars level 4.
Pin Crusher	Complete Court Curling level 4.
Pot Shot	Complete Block Buster level 4.
Zoo Feeder	Complete Shopping Dash level 4.