Project Overkill [NTSC-U] ISO
[SLUS-00045]

Released nearly a year after the Playstation's debut in the US, Project Overkill looks to be one of the earliest titles developed for the system. (Note the low SLUS #).
It's a gore filled isometric shooting spree with a robotron X control scheme similar to Apocalypse. Sadly the game predates the Dual Analog / Dual Shock, making the controls somewhat difficult to adjust to.  Gameplay generally follows a formula similar to DOOM except in isometric form. Kill enemies, collect ammo and health packs, find key cards, avoid traps and hazards, fight bosses, and make your way to each map's exit.
The player selects one of four agents at the start of each mission who's stats like health and ammo will carry over at the conclusion of each level. Each completed level acts as a hub which provides branching paths to other missions. As a result there is a hint of strategy involved with roster rotation and mission selection. 
Overall Project Overkill suffers from awkward controls, and a bit dated graphcis, but there is a certain charm to carving a path of death in destruction with a machine gun, as the death animations of your victems are grisiy satisfying.