Breach 873 grenades
"Breaching" a grenade disarms it, so naturally you will have to wait for an enemy to hurl a grenade to you. Just aim at it and hold
. Disarming a grenade is extremely fast, and sometimes you can finish breaching before it even hits the ground. After a grenade is tossed, you have around 5 seconds to disarm it and subsequently loot it for your own use. There are two bosses you can grind this on: Kris, and the final boss.
Kris (Ch. 15), when in the second stage, will begin to toss EMP grenades. If you take him to a sliver of health, he will throw three at a time. He will run and throw a set, and if you managed to not get EMP'd, he will walk a few feet and repeat. On easy mode, it's impossible to die, even if you mess up.
The final boss on Chapter 20 is the other boss you can grind this on. After you kill the twins, down final boss' health by a bar or two so he's dropped his minigun and just run around the area disarming the grenades he shoots out every so often. This is also recommended doing on easy mode.
Warpath - 5
Get the rampage bonus up to 5 sequential kills
It's pretty easy to get this without trying in single or multiplayer. You need a rampage with 5 kills. Aim for a kill a second. In single player, the first Aspari level towards the end has quite a few opportunities to get this, even on hard mode. In coop mode, there are a ton of opportunities to get this if you play on normal by yourself. If you're having trouble, level your character up, fully upgrade the sniper rifle, and let guys pile up. The sniper will rip clean through a group of people, and you have 8 rounds to play with.
Make It Snappy - 10
Kill 50 enemies with melee executions
Melee executions require you to stand next to an enemy and clicking
. Note: not all enemies can be melee'd. All of the lower class soldiers can be melee'd, however. Just click the stick if an enemy is too close to your sniper rifle. This can be done in single player or coop, or any mix of the two. Coop chiprips count toward this.
Nowhere To Hide - 30
Use a penetration weapon to kill 500 enemies through cover, while in DART Overlay
The weapons that count for this are the Kusanagi rifles in scope mode and the COIL's secondary fire. After the penetration is upgraded on the rifles, it will shoot through moderately dense walls at an equal level of the COIL's secondary. It won't plow through thick bunker buildings, but this achievement is a breeze with an upgraded rifle, since you can take it as a loadout option. Just pop your DART-6 overlay and shoot anyone that's behind cover. Of the two loadout weapons, the sniper will be easier, as it does more damage, and with damage link, one shot's everything.
Collect 500,000 energy
Energy in this game is adrenaline, so don't let the description fool you. Adrenaline powers your applications and helps keep your DART vision filled. You can keep track of this statistic in the extras menu, under campaign and coop. It will come naturally as you complete the other achievements, especially while playing multiplayer.
Hacker - 30
Use breach abilities 300 times
This only counts abilities, not any moment where you're just using the "breach" ability. For single player, this includes suicide, backfire and persuade. For multiplayer, this is any ability aside from the default "breach" ability. This should come with time getting the other achievements.
Rampageous - 15
Do 250 rampage kills/kill streaks
Rampages are a quick three kills or more in rapid succession, and it seems to count when the deaths are one after another, rather than at the same time. Damage link works wonders for this along with the sniper rifle using the assault scope, or an upgraded minigun. You will know when the kills you have just made count to a rampage in multiplayer when a "RAMPAGE 250" bonus shows up on the screen. In single player, you will have to just keep track of this in statistics menu since bonuses don't show up on the screen.