When you break open a crate, barrel, or any other object that makes items pop up, immediately hold Guard. All harmful items will land on you and disappear without any effect. This also works on helpful items and everything except for bombs.
Unlock the following Komas by performing the corresponding tasks. To easily unlock the Komas in which you must battle a certain number of times, repeatedly fail the "get hit once and you lose" missions in J-Adventure mode:
KOMA - HOW TO UNLOCK Goten Help Koma - Get 200 Koma Bobobo Battle Koma - Battle 350 times Naruto Battle Koma - Battle 400 times Don Pachi Battle Koma - Battle 450 times Hanamichi Sakuragi Koma - Get 450 Koma Ichigo Help Koma - Get 450 Koma Sasuke Battle Koma - Battle 500 times Ichigo Battle Koma - Get 540 Koma Vegito Battle Koma - Get all Koma Kakashi Help Koma - Draw a Konoha leaf emblem in the upper right part of the touch screen during the introduction sequence. Alternately, get 360 Koma. Sakuragi Help Koma - Draw a basketball shoe in the lower left part of the touch screen during the introduction sequence.
To change the color of the ink you use to scribble on the bottom screen, during the introduction, press L or R. The initial color is white; the other colors are black, pink, blue, cyan, green, yellow/orangish, red, and gray.