The Logan's Shadow Engine is a proprietary game engine developed by SCE Bend Studios. It makes use of popular physics engine, Havok, allowing for advanced physics in real time. It made its debut on the PlayStation Portable, in the game Syphon Filter: Logan's Shadow. Since then, it has been used to power many PSP titles. It is assumed that since the PlayStation Vita replaced the PSP in 2012 as Sony's handheld console, the engine is now defunct. However, that is not entirely proven.
List of games that use the Logan's Shadow Engine
References
Logan's Shadow Engine Wikipedia(Text) CC BY-SA