According to Famitsu, the limited edition of the game, Corpse Party -THE ANTHOLOGY- Sachiko no Renai Yuugi Happy Birthday 2 U, will feature an OVA titled Corpse Party Missing Footage. Corpse Party started out as a horror adventure doujin soft video game developed by Team Gris Gris in 1996, followed by a series of remakes and sequels that were licensed by Square Enix USA to be released in the US and Europe. The newest Corpse Party will be released for the PSP along with the OVA on August 2nd, 2012 in Japan.
Famitsu has also announced the release date of the PSP game adaptation of Ano Hi Mita Hana no Namae wo Bokutachi wa Mada Shiranai, to be on August 30th, 2012 in Japan.
Source (Japanese): Famitsu
Corpse Party: Missing Footage on MAL