The chin is a bit misshaped and it has little vampire teeth (pika evil?)
And the left front leg is small and to thin.
The body of the Pikachu does not look round, more flat actually..
U can improve that by bending/curving the marks on pikachu back a bit.
And there could be more shading.
Teeth are there because well... I wanted him to look like that kinday a goofy way. Also notice the position of pikachu. The left leg is barley shown at all it is covered mostly by the head and it is further away from view.