It is hard to figure out, but doing so is worth it.
In this game you build a robot with monetary limits and fight other 'bots to earn money for better parts. The variety of parts is somewhat low, but the battling makes up for that. The controls for the robot can be very confusing and the AI is tricky from the start, but that is how it is on almost every GBA game. It is a simple game in concept, put it has a whole lot of replay value.
Graphics:
The graphics are good for the GBA, but not great. Some better graphics could really have helped the game with robots being hard to distinguish from one another, but they are okay for an isometric 3d game.
Sound:
Like almost every gameboy game, the sound is very annoying. I don't like a silent game though, so I leave the sound on anyway.
Overall:
Not worth the retail value, but if you find this used and cheap you should pick it up.