A two-piece is a term that Gears of War players have coined for a specific technique. The move is often frowned upon for its usual instant kill outcome and overall ease of usage. With a little practice, this is one technique that can be mastered quickly and is very useful.
To perform the two-piece technique all you need is your shotgun out and you need to be ready to melee. You start out by walking up to an opponent. You get close enough in striking distance and then you hit the melee button. If you connect the melee there is a moment of you and your opponent being stunned. It is just the animation of the characters hitting each other. If your opponent is rolling away or rodey running this animation will not occur and he can potentially be shot by you, shoot at you, or run away, so it is to your advantage to hit him while he is standing. Your opponent will recoil much more than you however. When your opponent is stunned you can do this in a number of ways, but the most important thing to do is only hit the B button once.
The only time a two-piece should fail is when someone pushes the B button twice. If you do push it twice, on your screen it will appear you have only swung once, and you are able to shoot. You can shoot, but the bullets will go right through your opponent, dealing no damage whatsoever. The truth is you never really shot your gun. On your opponents screen it will appear that you have meleed twice and in reality you actually have. This gives your opponent enough time to shoot before you and in all likelihood kill you. This strange outcome happens every time if you press the B button twice. It's do to the lag offset between you and the host. If you are the host, however, the game can read the twice pushed B button of two ways. It will either read it as two melee swings which will knock your opponent down, or it will read it as a successful two piece and kill your opponent. It all depends on how quickly you press the buttons.
Now that you have meleed your opponent and only pressed B once you can do this two ways, aiming or from-the-hip. When you melee you should still be slightly moving and strafing around your enemy. You want to be moving away from his gun, because if something has gone wrong (if he tries to roll, run, etc.) and he is aloud to shoot at the same time as you, you don’t want to be in the way of his fire. If things are going to plan you will be strafing him and he will be stunned for a second longer than you. If you plan on aiming, make sure your cursor is right on him. If your cursor is even half off of him or anything less than that, it will not kill him. Aim for the body, and if you have done everything correctly so far it should kill him. Now, if you planned on shooting from the hip, you will be strafing around and once you are pointed right at him, just fire and it should kill him. The only time it wouldn’t is if you didn’t hit him square on. The timing on from meleeing to shooting is different for a lot of people. There are a ton of variables to consider, so if you follow what I have said it should work most of the time. I have heard people that shoot right after and I have heard people that wait a half a second. The thing that people WANT to avoid is having their shots go right through them. The bullets won’t work because sometimes certain variables (lag, what the enemy is doing, etc.) aren’t working in your favor. This technique is not perfect by any means. But if you do it right, and master your own style of doing it, it should be an instant kill.
There are many reasons the community frowns upon this technique. Some people rely solely on this skill and people criticize them by saying that’s all they can do. Some people don’t like the move entirely, because you can consider it as a glitch. The truth is you are exploiting the games animation to get an instant kill. The reason the debate isn’t one sided is just because the move isn’t perfect. Overall it’s a great move to use if you are outnumbered, low on health, or low on ammo. Any veteran Gears player always has this move in their arsenal and will use it when they need to. Even if it does get a few angry sneers.