Metro 2033

You can get both sticky and regular grenade kills towards the end of the level Ghosts when there are 3 separate groups of rats in two adjacent rooms with 5-6 rats in each group. You will need to run ahead of Khan to prime and throw the grenades before he activates the respective groups' movements (their locations are very obvious). The checkpoint is also right before this section.

It should be noted that I did not receive the "Ka-Boom!" achievement at the same time as the "Sticks like a bur" achievement, though a quick checkpoint reload solved that problem.

Credit for this solution goes to O918 on XBA.

Can be done all throughout the campaign, but if you find yourself completing the game without it, I recommend the level "Outpost" from chapter 4.

General grenade tips:
- If you are trying to hit large groups or even sometimes individuals, you will need to cook the grenade for a few seconds before throwing it, otherwise they will easily run out of the way
-If you have nail grenades, try and stick with them, its an easy guaranteed kill.

(If you don't have any grenades when starting this level, you could always play the level "Child" before it, and at the end of that level you will get the chance to purchase some - I started with 5 normal grenades)

In short:
- 6 easy kills from the patrol right at the start
- 2 kills from the nail grenades found above the patrol (on the metal bars)
- 2 kills anywhere else using the 5 or so spare grenades you should have.

In-Depth guide:
Get out of the tunnel at the start, and once you get into the open and can see soldiers, immediately turn right. Go into the bottom right corner, and you will find a ladder. climb up to the top and creep forward until you have a good vantage point of the 6 man patrol. Wait until the patrol stops and starts talking, then try and kill them all with as few grenades as possible. I managed to do it with a bit of practice in 2 grenades. That is 6 kills, you now only need 4 more. Kill the single guard on the upper levels (he more then likely attacked you after you threw the first grenade) with a gun, or a grenade if you feel up to it. climb up (as if you were playing the level) and in the middle of the metal bars you are walking on you should find 2 nail grenades. DO NOT throw grenades from here at the 2 soldiers shooting you - you WILL miss. Run up close to them and try and stick them with the nail grenades. That's two more kills, and you should have around 1 or 2 more grenades now, but if you don't, don't worry. Ignore the guy that runs out of the house, and throw a grenade into the room he ran out of (the room you want to go in) and you should have another 1 or 2 more kills. Now that you are in the close-quarters of the house, you should be able to get some kills quite easily. So from here, I will just list the locations left in the level where you can still find grenades (In case you missed with some throws) Approximately 1 on the top most level of the house on one of the soldiers, and 2 more at the radio station (where you put the tape recording if you have it) and then 1 or 2 on soldiers in the very final patrol before the level ends.

Good luck!

Edit: I didn't have any trouble unlocking this achievement, but it seems since the recent update may have broken a few achievements. If you are having trouble getting this achievement to unlock even after fulfilling the requirements, try clearing your xbox 360's cache, deleting the DLC and your save game, then playing offline. Thanks to Hybridchld for this tip.

I found the easiest way to obtain it was on the level "frontline".

First make sure you got 5 sticky grenades and 2 regular. If you don't have sticky grenades load up armory mission and after the chase segment you can buy some.

The regular grenades are easily avoided by the enemy (you can cook them up though), but there are 5 enemies that won't avoid your grenades. The enemies that won't avoid them are:
1) The 2 wounded soldiers you find
2) the 3 red army captives
that should make 5 easy regular grenade kills.

the other 5 kills are easily gained with sticky grenades, just get close to an enemy and trow in onto them. If you did it correct the grenade should stick on the enemy and kill him.

Hope this helps you guys :)

Ghosts and Frontlines didn't work for me, God knows why cos I did more than 10 on both levels, so I ended up getting it on Chapter 4:3 Depot. Let the soldier at the start raise the alarm and then get ready, stay crouched and on the platform will be loads of soldiers who don't seem to run from grenades. You should have it by the time you reach the nosalises. I used standard grenades for this.

I found that "Frontline" was a good level to get this achievement. Anytime I found myself faced with more than 1 enemy, I would light up a grenade, cook it for a second, and let it fly. There are several occasions with multiple enemies and there are are several crate locations that contain more pipe bombs so if innacuracy is an issue, you have many more opportunities to get this.