Embodiments in accordance with the present invention provide an opposed piston, opposed cylinder (OPOC) internal combustion engine. The OPOC engine comprises two cylinders opposed at 180 degrees. A linking element connects two outer pistons so that they move in tandem. A central piston is disposed between and moves in opposition to the outer pistons. The linking element is adapted to drive secondary mechanisms in accordance with embodiments of a drive shaft, electric generator, hydraulic pump, pneumatic pump, and gear-driven mechanisms, among others.