Last week, Cave Story's ESRB rating was updated to include new platforms: PS2, PS3, Vita, and Xbox 360 in addition to the existing 3DS, DSi, Wii, and PSP ratings. We contacted developer and publisher Nicalis to determine whether to expect Cave Story on even more platforms than it's already on.
In short, no. The ESRB ratings are not indication of definite plans. "We submitted all the consoles so that we wouldn't have to resubmit in the future," producer Tyrone Rodriguez told Joystiq, "IF [emphasis his] we ever decided to bring to those consoles."
The good news is that you are very likely to already have a platform to play Cave Story on.