Theres 4 bonus missions Mr Blondes Revenger for finishing on Agent Maian SOS for finishing on Special Agent WAR! for finishing on Perfect Agent Duel for getting at least a bronze on all weapons in firing range

New difficulty setting called Perfect Darkness unlocked by beating all levels on Perfect Agent

You can cheese some of the firing range by selecting the laptop gun on bronze, turn to the wall behind you (or where ever you want it) and throw it, when it folds up and disappears out of sight but before its thrown pause the game, cancel out of laptop gun, and choose the one your having issues with. Once it starts the laptop gun should then finish throwing and help out.

Loved playing through the game again but on PC