There's a weird meta-irony at work in Custom Robo Arena: a young boy wanders his town, goes to school and eats with his family, spending every free moment playing with his Custom Robo game; you, as a gamer, wander your town, go to school, eat with your family (hopefully), and spend every free moment playing your DS. In an odd way, you can relate to your tiny single-minded friend. It's also a game that's much more fun and charming than you'd expect, regardless of your predisposition towards handheld battling robots.
After being thrown into your first Robo battle from the menu screen without introduction or instructions, things thankfully calm down a bit. As a new boy who just moved to a new town, you're given your first Custom Robo, the Ray Mk II, as a birthday present from your father (who just happens to work at the local Robo research center, along with your sister). Turns out everyone in town, from classmates to teachers to cops to criminals are Robo nuts. There's sure to be a message in here somewhere about our obsession and reliance on technology, but these people are even more addicted than we are. After joining one of your school's Robo teams and quickly proving yourself a talent, almost everyone you meet will want to take you on.
Thankfully, the matches themselves are short and sweet. They take place in portable "Holosseums" that you "dive" into to control your Robo with mental energy. Touch-screen controls would have been awkward in such fast-paced, 3D fights, so they've thankfully stuck to the directional pad, face buttons and triggers for combat; touch screen controls are used only for menu navigation and, er, cleaning your robot's dirty bits in between bouts. The arenas are small and littered with low walls and obstacles, though they vary a bit depending on who's battling.