Astro Boy is the Mickey Mouse of Japan as well as a Great side scrolling shoot em up game for the GBA
In this great side scroller you play as Astro Boy, blasting your way through the levels with lasers a butt machine gun and a powerful arm cannon that decimates anything in its path. All your abilities can get upgraded for more agility and strength. There are many characters that you must meet in order to level up and gain access to your Omega Factor, which is actually another name for your soul.
The action is fast paced and the graphics are amazing for the GBA. Great character and level design. Good replay value too since its going to take you some time to find all the hidden characters in this game.