Wall Mine - Flash

Wall mines are less effective in Double Agent than they have been in the past, but the flash variant is perhaps the most superfluous device in the game. Even if you somehow manage to lure a guard into an area where you’ve set one of these and make it go off, you’ll still have to manually reach them and either grab them or disable them before the effect wears off, which will be a relatively short amount of time. It’s far better to just get good at whistling soldiers into dark places and disabling them manually, without worrying about technical niceties.

Shotgun Shell - Attachment

The shotgun in this version of Splinter Cell is an unlockable upgrade for your SC-20k. On hard mode, this is going to be one of the few lethal ranged takedown measures you have, but it’s almost always going to be a poor choice for any kind of killing. It’s loud, inaccurate, and inefficient, since you’ll only be getting eight rounds for it per level. If you ever get backed up into a corner with a full alarm going off and guards coming for you, it might be your best bet to fend them off, but in most cases (at least how we play), such a situation is generally better resolved by loading a previous save.

Hacking Device - Software Upgrade

This upgrade speeds up the amount of time it takes for your hacking device to lock down possible numbers when hacking a computer. Not something you want to do without.

Smoke Grenade - Attachment

This attachment lets you fire smoke grenades with your SC-20k. There aren’t too many ways in which this varies from the regular smoke grenades that you throw by hand, but they do get to their destination more quickly.

Sonic Grenade - Attachment

As with the thrown variant of sonic grenades, the launched version probably won’t be of much use to you. The stunning effect doesn’t last very long, usually giving you barely enough time to knock someone out if you run towards them. It’s simpler and usually less risky to just lure people into the dark and deal with them there.

Hacking Device - Force Hack Upgrade

The Force Hack upgrade allows you to instantly override any hackable computer by tapping the X button, thus letting you avoid the usual minigame that accompanies hacking. This is a great way to quickly hack into a computer, with a couple of drawbacks: it’ll take points off your stealth score at the end of a mission, and it’ll cause the computer to emit a soft alarm that’ll bring over any nearby guards. Generally, this is best used on computers that are somewhat exposed to guard lines of sight, which you need to access quickly before retreating to a nearby shadowed spot.

EMP Grenade - Attachment

Same thing as a thrown EMP grenade, but launched. Still rarely ever needed to get past an obstacle; if you need to disable an electronic device at range, your pistol will be a better option.

Gas Grenade - Attachment

Launched gas grenades seem to disperse into slightly bigger clouds than the thrown variety, making them a bit better at taking down crowds if you need them to. Still a messy way to go, and just as likely to draw an alarm as it is to go off smoothly. Still, when they work, they can save you a whole lot of trouble.

Frag Grenade - Attachment

Frags launched from your SC-20k are, again, more or less the same as those thrown by hand. Enemies will still attempt to dive away from them when they hit, but since launched grenades still move more quickly than the thrown ones do, you stand a good chance of getting somebody dead. As always, though, these make a big bang and will attract a lot of attention, so they’re really only useful if you don’t mind setting off alarms.

Night Vision - Enhanced

Enhanced Night Vision will be an improvement over regular night vision, but not stunningly so.

The final upgrade unlock is enhanced night vision, which is basically your standard night vision - but with colors! That’s right, instead of a fuzzy green view, you get a fuzzy full-color view. This is more or less an aesthetic difference; you can see people moving around just fine when the nightvision is green. Enhanced night vision, then, is basically a large gamma correction to make the dark spots much brighter than they were previously. Unfortunately, this can sometimes make it difficult to tell whether or not a semi-lit spot on the ground will be green or yellow on your light meter, making it generally more necessary to flip back from NVG to regular vision before moving in a sensitive area. On the plus side, you'll be able to see the light meter on Sam's back more easily.