Onimusha Tactics Cheats - GBA

Easy experience
Find a stage that your character could first fight with an enemy, or any stage that your will touched the enemy before the enemy fights you. Then, choose the lowest level character from your team, and train it in the stage. For example, after you just touched the enemy and gain the little bit experience (about 48 experience points), and just before all your team members end their turn, escape from the match. Then start over. Continue doing to earn a lot of experience.

Play Episode 9: The White Tiger Camp: Conclusion level. You will battle the twin monsters (Gullikeen and Dollikeen) at the same time on a mountain, if you kill one, the other will throw a Recovery Bomb and revive his brother. To gain easy experience and a nice amount of good recipes, mass your entire army at the top of the mountain and snipe all of the Jahinoons, but make sure you stay out of the Boss' range. After that, have everyone attack the Boss on the same turn and you should be able to kill him. After doing so, place one idle unit (if available) on top of the ground where the fallen Jahinoon stood. This will prevent his revival. Heal, then on the next turn, move the blocking unit off the Boss' ground and end the phase. The Boss will be revived and attack one of your units, but you can Heal. Note: Make sure it is not a weak unit like Oboro (bring her along to heal). Continue this tactic and you can get lots of experience, and many special recipes such as the Yin-Yang Clothes, some good recovery items, and the Moonglow Bow. When done, leave one unit on top of the Boss' corpse and send the rest down to take out the twin.

Onikko (The Oni Kid)
Survive all of the floors in the Phantom Realm. Eventually Mr.Yama will ask you to bring along a little person named Onikko. He is at level 1 and is an axe wielder.