Weapons can be upgraded as your progress through the game, but upgrade stations are rare, so you really have to consider which will get the most use. We found the shotgun very useful, so we were sure to upgrade its rate of fire and its damage rates -- making it a formidable death-dealer.

Special powers, earned through gene-altering "plasmids," bring in several more layers of customization. These drugs enable Jack, with a simple hand gesture, to light enemies on fire, shock them, freeze them, make them targets of the city's built-in security system or injure them with swarms of bugs that erupt from his arm. While running around injecting oneself with random needles found on the ground (the source of your plasmid's power) would be inadvisable by the FDA, those rules don't apply in Rapture.

A maximum of six plasmids can be kept active at one time, so players must pick their poison until they reach a gene bank that allows them to swap powers out. This can be inconvenient at times, but it also makes the game that much more challenging. Some powers will get more use than others -- we found mixing and matching the shock, fire and ice powers with weapons to be especially effective for standard combat.

Gene tonics give a permanent boost to Jack's other abilities. These tonics will make him more immune to damage, invisible to security cameras and also allows him to hack into locked areas more easily, etc. Like the plasmids, some tonics are more helpful than others -- so it requires using brainpower to pick the ones that will work best.

Hacking into machines via puzzle solving can also work to the trigger-man's favor. Bump up those security smarts and then hack into the city's built-in defense system, forcing it to turn on its residents. Or, pretend like you're George Clooney in Ocean's 14 and hack into safes to score some big loot. A hacker's job isn't always easy in this game -- and at times the simplistic hacking mini-game can get tedious -- but reaping the rewards make it all worthwhile.