Official versions of Mortal Kombat vs. DC Universe were never released for the PlayStation Portable (PSP). The game was developed by Midway Games Warner Bros. Interactive Entertainment exclusively for the PlayStation 3 in late 2008. The "PSP Version" Explained

If you are looking for high-quality, official fighting games available on the PlayStation Portable that provide a similar vibe:

Mortal Kombat vs. DC Universe on the PSP is often overlooked, but it is actually one of the better fighting games on the system. While the console versions (PS3/Xbox 360) were criticized for being a "toned down" Mortal Kombat game, the PSP version stands out because it successfully squeezes a full 3D fighting experience onto a handheld without the massive lag or loading times that plagued other PSP ports.

Bridging the gap between 3D weapons-based combat and crossover appeal, Broken Destiny is essentially Soulcalibur IV on the go. It features incredible graphics for a handheld and even features Kratos from the God of War franchise as a special guest fighter. The Legacy of Mortal Kombat vs. DC Universe

NetherRealm Studios (formerly Midway) missed an opportunity. In 2008, the PSP had a massive install base. A stripped-down port featuring 12 characters (6 MK, 6 DC) with an exclusive "Arcade Ladder" could have sold millions.