Space Invaders Pocket for PSP was released on May 12, 2005 in Japan.
It was then released on the Japanese PlayStation Store on October 1, 2009 [Model NPJH-50089]. This re-issue was published by Square Enix.
Space Invaders Pocket was the first UMD released in Japan to include a BIOS version checker for the PSP.
"Majestic Twelve", as featured here, includes new content intended for its original arcade release.
Programming errors present in the original "Space Invaders
" were intentionally reproduced.