Electron and ion dynamics are investigated through particle simulation of a supercritical oblique collisionless shock. As &thgr; deviates from 90°, ions are accelerated and trapped in the electrostatic wells and later become detrapped; this results in strong ion heating perpendicular toB0. Below a critical angle &thgr;teelectrons are strongly energized alongB0, and heated. A large parallel electron current builds up and induces new transverse electromagnetic components in the ramp of the shock. For weaker angles, ion heating vanishes below a second critical angle &thgr;ti.