SH4 is gaming's most enduring WW2 sub sim franchise returned to its old spawning grounds, the Pacific Ocean. Where SH2 and SH3 required you to chloroform your conscience, sinking British and American merchant shipping as a dastardly Kriegsmarine U-boat captain, this episode lets you feel good about drowning the defenceless. This time you're cooped-up in a sweaty US sub and your targets are those Pearl Harbour kidney-punchers, the Japanese.
For those who've never tried a sub game before, they're like stealthy FPSes with limited weapon choice, minimal scenery, huge levels and super-slow bullet-time. Well, kind of. Most of the time you're cruising around 'topside' looking for something to kill. When that something - a lone merchant, convoy or taskforce - presents itself, the ambush excitement begins. You plunge to periscope depth, and plot an intercept course that puts you just ahead of the prey and abeam of it. Once in position - if you're playing with high realism settings - it's all hands/eyes to the periscope; information about target type, speed, and bearing must all be fed into the TDC (Torpedo Data Computer) before the torps can be unleashed. With less-demanding settings, fire preparation can be as simple as locking the unwitting victim in the crosshairs and waiting for the target icon to turn seaweed-green.