Megaman Starforce 3.
First of all, it never recieved a release out of japan and the USA. Also, Nintendo WFC is down and thus an important game feature is down: Multi-Noise and Brotherbands. Meh, atleast Rogue Noise is really OP.
Oh and navigation in the post game astro waves is atrocious. The difficulty for the final boss and the post game bosses spikes up dramatically and dont even get me started on Crimson Dragon Sigma. There is a reason he is the last boss you will fight. Turns out Sirius Sigma is less powerful(The True Final Boss with like, 4x power).