Kokuga, the spiritual successor to Treasure’s Ikaura, which so happened to be a spiritual successor itself to Radiant Silvergun, will be released on the 3DS eShop in Europe and North America this June or July. Japanese players have been playing this non-linear, top-down, tank driving shooter since last September. The game features 15 free-scrolling levels and a 4-player download play option.
Source: Nintendo World Report
I had no idea this game existed! Count me in; Ikaruga was pure awesome and this non-linear shooter idea has my head swimming. :^)