A Japanese game developer & publisher responsible for some great titles, such as:
* Pac-Mania (Pac-Man with Pixar style graphics and jumping)
* Galaga '88
* Dragon Spirit & Dragon Saber
* Assault (tank game with Mode 7 style special effects, even better than what the SNES can dish out though)
* Splatterhouse series
* Ridge Racer
* Time Crisis series
* Tekken series
* Crisis Zone
* Razing Storm (the "Complete Destruction Machine Gun Game"- very good whether it's at the arcade or on PS3)
* Deadstorm Pirates (if you can't find it at your arcade, it's in Time Crisis: Razing Storm for PS3)
... and many more.
Namco's lightgun games are seriously worth checking out.