Star Wars: The Force Unleashed

Lightning Shield is when you hold LT and hold down Y until your Force meter flashes yellow. It's best to do this somewhat out of the fray of battle because if an enemy knocks you down it will mess up your shield (you'll have the shield but it won't be powerful enough to kill anyone)

You will need to have your corresponding force talent upgraded to at least slot 2, preferably 3 for this to work.

You'll know you do this correctly if you are surrounded by a white orb that shoots lightning at anyone near you. To get this achievement, just let the lightning from your shield kill your enemies. It doesn't count if you kill them with your Saber (although weakening them with the Saber is fine)

Best done on a second play-through with an upgraded character in the Tie Fighter level as there are a lot of regular-strength Storm Troopers in this level that are killed rather quickly with the Lightning Shield.

In all likelihood, you got this game to play through it, and if you're like me, you glanced at the achievement list, saw lots of "kill tons of enemies," and you thought to yourself: "No problem, I'm playing through the entire game. I'll pick it up as I go along."

Now, you're sitting there, like me, wondering where to go with this after completing that story mode since you cannot replay the prologue AND your kills won't carry over to your Sith Master save, nor can you carry them over to that Jedi Temple DLC. That means all of the wonderful solutions you've been reading won't work at all if you want to keep all of your progress. Are the Jedi Temple and Prologue good places for this? Sure, if you haven't started or want to start over.

My personal grinding point for this and all the other "kill with skill" achievements was the Tie Fighter Factory, right at the beginning at the level. You spawn in a hallway with some droids (wipe them out if you haven't grabbed the kill 35 droids achievement; oh yeah, and the droids of my enemies are my enemies so they totally count as kills too), and once you get to the end of this hall, you bust the door open with Force Push, and you're in a room with some rebels and some Stormtroopers. At the far end of the walkway where you enter is an unlimited force powerup.

Lightning Shield is where you hold LT, then hold Y to charge the shield. Once you see it sort of flash (and if you're not on the unlimited energy, your force bar will turn yellow), you're ready to kill stuff with it. Trouble with laser bolts deflecting? Reset the yellow talent spheres in Force Upgrades under the pause menu and build them all back up except Defense Mastery to lower your ability to deflect the bolts.

Clear the room which is about 40 or so enemies (nearly 50 if you grab the six droids in the hallway as well; yeah, the droids of my enemies are my enemies). Pause the game. Save it. Select Mission Select, then Tie Fighter Factory, and then Load Previous Save. You'll start at the beginning of that droid hallway. Do it again and again and again until you get the achievement, then pick your next skill, and do it again.

How long will it take? Depends on how many you did during the story since this method at least respects that you probably have some kills on it. Happy grinding.

If you have access to it, you can get this achievement fairly easily right at the beginning of the Jedi Temple DLC.

Start a new game, select 'Jedi Temple DLC' from the options and set the difficulty to Apprentice. After dropping down from your ship to the temple entrance exterior, hold and then press and hold until you generate a lightning shield. The shield should make short work of the surrounding stormtroopers on the first platform but be sure to run around to finish off any stragglers.

You can either keep doing this until all the stormtroopers in the area are eliminated (but this will require waiting for your Force energy meter to recharge) or you can just jump off the platform, committing suicide and respawning back in the interior of your ship at the beginning of the DLC. Here you just repeat the aforementioned steps until the achievement unlocks. (Note: Your kill tracker carries over so there's no need to worry about dying and losing your progress)

This method can also be very efficient for acquiring the Force Lightning Mastery achievement as well as the two Force Repulse related achievements as there's no need to wait around for enemies to respawn, unlike the abusing the infinitely respawning stormtrooper method during the Darth Vader prologue.