Gears of War 3

This achievement requires you get earn any one of the 65 different onyx medals. The easiest and fastest medal by far is the one called "Doorman" it requires you to manipulate 2000 objects in the campaign.You earn credit towards this medal everytime you press a button, pull a lever or open a door etc.
Load up Act I Chapter I, after the cutscene with Jace you will climb up a staircase and open a door, right in front of you will be a piano. Walk up to it and press X to "play" it. Mash your X button for about 1.5 hours and you will have the easiest and fastest onyx medal in the game!

You should also keep in mind that you will earn a onyx medal for completing the game on insane, if you plan a playthrough on that difficulty you won't need to worry about this achievement.

For the full list of onyx medals, check out my Seriously 3.0 guide:

In my experience, the easiest (probably the funnest aswell), is to get about 4-5 of your buddies, head into Beast mode and beat it on Insane without failing a round. If you do however end up failing, you can easily restart back to wave 1 without having to go back to the lobby.

TIP: Have 4 guys be exploding Tickers, and the other a Wretch (I say wretch because it's the 1st tier of beasts so you can start right away). Have the Wretch go near the enemies and press X to do the "scream", which stuns enemies for a few seconds, then have the tickers rush in and blow em away.

When you get about halfway through, have at least 2 people be the Giant Serapede. It is VERY effective (especially against Silverbacks), and it's really hard to kill.

Also, make sure at least 2 people can be Berserker and one a Boomer when you hit Wave 10 or 11. Wave 12 isn't all that difficult because of the lack of COG Heroes, so it can be accomplished doing it with the Serapedes and such.

My buddies and I only restarted once doing it this way and it took about 20min.

EDIT: Forgot to mention, best map to do this on is Trenches. It's small and has some good flanking routes and the humans are almost always outside of their fortifications.

The easiest way I found to get an Onyx Medal is in Horde mode where you need to make "1,000 Fortification Modifications":

An easy solution is get a second controller and log in as a "guest".
Start up a private Horde match.
Set it to any difficulty you want because it doesn't really matter all that much, unless you suck in which case make the difficulty fairly easy. :P
I used Checkout for the map, doesn't matter what map you choose really, I just preferred Checkout.
When the match starts use one of the controllers to "build your base", doesn't matter which controller you use as it costs nothing to build your first base.
Take control of the "guest" account and give all the money to your main character.
Build a turret with the money you've been given.
Make the "guest" take control of the turret and start firing.
As the turret's firing, spam Y when you're next to the turret with your main character and watch your money slowlyyy go down.
During the rounds make your "guest" account go into cover so it doesn't die. And when the rounds over put 'em back at the turret and rinse and repeat.
It'll take a few rounds if you have 0 fortification modifications, but if you have 500+ like I did, it'll take 5-10 minutes at the maximum. :)
ALSO, this can only be done between rounds as you can't upgrade or build fortifications during rounds.


HOPEFULLY I made all that sound clear.

Difficulty: 5/10 OR 1/10
Time: 8 hours OR 4 hours
Entertainment: Very High OR Soap-Opera Boring

For this achievement, you have to earn at least one "Onyx" Medal, which is essentially the fourth stage of a medal that has levels to it. You can check it by going to "Stats & Awards" from the main menu OR a campaign/Horde lobby. There are basically two methods, one requiring you to play a bit of multiplayer and then jet through the campaign and one that requires you to just sit at a piano and press the "x" button for about four hours. The two medals are:

1) Beating the game on Insane
2) Interacting with 2,000 objects in the campaign

1) This is probably the least boring medal in the entire game, however, one of the most challenging. However, there is an incredibly easy way to make Insane feel like Normal. This, however, takes you to earn a certain mutator. The mutator requires that you earn a bronze medal for all your starting weapons, which is getting 100 kills with the weapon. The weapons are;

Lancer
Hammerburst
Retro Lancer
Gnasher
Sawed-Off Shotgun

There is a very easy way of doing this. Just make a private match with full bots set to "Casual" difficulty, then set the mode to King of the Hill and the map "Mercy". Get all 500 kills, you will get eight bronze medals along the way, netting you some nice progress on S3.0 and ranking you up! Here's the best part; the mutator, when you perfect reload, makes all guns a one-to-two-shot kill with ALL weapons on ALL enemies, PLUS it doubles the magazine size of your weapon. For example, if I have a Sawed-Off shotgun, I perfect reload it, I not only get the damage significantly multiplied, but I get to shoot TWO BULLETS! This makes the entire campaign a breeze beyond belief! The final boss literally takes three bullets to take down to Hammer-of-Dawn it! Also don't forget to put it on Arcade, for when you die on Arcade, it doesn't end the game; you just spawn in thirty seconds!
This is a very enjoyable way to playing the game with some buddies, so if you get three friends to come along with you, make sure the host sets the difficulty to Insane, Arcade Mode, and activates and ONE mutator, and it takes eight hours to beat the game! You'll get two Onyx medals (One to beat the game on Insane, one to beat it on Insane under Arcade mode), and a slew of possible achievements! They are:

- 50G: Ready for More
- 50G: Ain't My First Rodeo
- 75G: That's Just Crazy
- 25G: Award Winning Tactics
- 50G: My Fellow Gears (If you play with 1-3 friends)
- 50G: We Few, We Happy Few... (If you play with 3 friends)
A total of 300G! Or...

2) ... you can do this. At the beginning of Act 5, Chapter 5, there is a piano in the mansion you spawn in. If you go up to it, you will be prompted to hit x. You'll hear Marcus beautifully slam the piano with his fingers, and if you do this 2,000 times, you will get one Onyx medal. Simple, but indredibly boring.

Obviously, I recommend the first option, if you didn't sense the bias by now, haha.

Here is a simple, no-nonsense Youtube video on how to gain the Onyx Medal Field Engineer. MAKE SURE whomever is trying to get the onyx is the host, and like the video says if you are planning on getting killed in between waves it would be a better idea to put the difficulty on Insane, rather than normal or casual. This should take beween 5 and 10 minutes. Hope you all enjoy.

Credit to DirtiestJordan for great video.

Another way of getting this is on act 5 chapter 2 called blackout start the level you'll start indoors then go outdoors and then back in and when it mentions the you have to find the generator room keep a lookout for a room on your left and you'll find an American football table ,when you get to it it'll promp you to press X keep pressing X and it'll count towards the oynx medal you have to press it 2000 times ,it takes about 3 minutes per 60 times you press X so it'll take at least an hour ,hope this helps ,if anybody is struggling give us a message and I'll show you where it is
there's also one on act 1 chapter 1 at the beginning when you go upstairs

My first onyx medal was "killed 1100 humans in Beast-Mode".

I didn't want to boost this achievement so I just played the game.
To be honest, I got this achievement really quick, because I was hunting the "Instagib Melee-Mutator" - so I needed 200 wretch kills.
While doing so I realized that getting kills with the wretch is really easy, because you can sneak up on the enemy, temporarily disable them and avoid traps/fortifications in the early state.
I recommend you use the wretch until the fortifications are upgraded to laser-spikes.

Now, you can pick the Mauler or the Kantus. The Mauler makes good areal damage on enemy and fortification clearing the way for your teammates, while the Kantus assists with perm-healing/reviving. The Ink Grenade is also very useful, so you can easily down/kill enemies.

Now the most important part - Savage Grenadier. The Shotgun is a bit weak on distance but the grenade is really important. You can take out/down 4-5 guys easily at once. For example, on the motel map, when the enemy gathers in front of the motel where Anya usually likes to shoot a Mortar. Just hide behind a car and throw a nade. Works out fine.

Optionally, you can use the Zerker, but I don't really prefer him because I am not that flexible with him. I usually use him in Wave 11/12 for Ready for the Heavies or to get money, because the Onyx Guards are kinda good on evading the Zerker-Smash.

Another solution might be, that you play the campaign on insane difficulty. Works really easy with instagib melee and super reload. I managed to play it all by myself until chapter 5.

PS.: This is my first solution. So if you want to criticize my solution go ahead, but please don't leave negative votes without further explaining :)

Looks like these solutions haven't been updated too recently. The easiest and least time consuming Onyx Medal to get is now "War Supporter".

With everyone being bumped up to 29/30 games played, just jump in a special event playlist, play a game, and voila! Achievement Unlocked.

You WILL also get "Socialite" at the same time (since if you had that, you'd have this!)


Edit: dc0dr's guide for Socialite lists many events and some info about them.