Gears of War 3

Different view than Kevin. If you have played the other Gears and if you finsihed any on issane than I suggest doing it as your first play thru. I did the campaign on Hardcore and took my time and got all the collectables also. While doing it this way probably added several hours to my first play thru(plus to find my way in a few scenes I got hung out to dry or moved faster than the AI leaving me exposed) I found it very satisfying yesterday when these all popped up.

Keys: cover, cover and more cover. I noticed in this version that the muzzel flashes plus my higher use of grenades meant that I didnt always pick up on the on-screen damage indicator due to the busyness of the graphics. On some of the hectic firefights or when scoping in I found I suffered from tunnel vision and "looked "thru the damage indicator more often than in the previous 2. Hope that makes sense...

Dont trust the AI, I did play this playthru solo, I suggest co-op if you can, especially for the final battle. I was hanging back w the hammer and got shot in the @ss too much cause my a.i. teammates moved further down and wouldnt always respond. I also noticed that to get them to revive me that I ahd to crawl on a direct intercept path cause they would over run me if they respond at all.

Grab ammo whenever, sometimes it gets thin so grab early and often and dont hesitate to switch guns even if you have a cool "skin", bullets are better than bling. I carried a Lancer and Hammerburst a large majority of the time and swapped the Hammerburst for a limited large weapon from time to time however I did rely on firepower over style.

Worry about executions later, concentrate on survival, the Locust seem more prone to flanking and I noticed chainsaw and executions up'ed my chances of being flanked.

Hope that helps, enjoyed the campaign a ton and felt very satisfied finsihing it solo on Hardcore, debating on a solo insane but not sure if my nerves could stand the AI again at that level.

The best way to get this achievements (and the other difficulty related achievements) is to get these mutators instagib melee, infinite ammo and super reload.
The effects of these mutators are the following. Instagib melee: you kill every enemy with a single melee hit (except for bosses). Infinite ammo: well pretty much what it says (sadly only works on these weapons: lancer, retro lancer, hammerburst, gnasher, sawed off, all the pistols and the cleaver). Super reload: when you make an active reload you get a 2x ammo clip (this doesnt disappear after a while) + massive damage bonus (you can kill a reaver with less then half a clip on insane). Once you have them start a game of arcade campaign. Now just play the campaing normally and try to make as much super reloads as possible since you kill drones with 2 bullets, and since you have infinite ammo you can just shoot as much ammo as possible. You can also make it easier by getting a second controller and just let him sit somewhere safe. Now you can just die and the chaper wont restart.
Good luck.

Edit: since people wanted to know how to unlock these mutators ill add them.
Instagib melee: kill 200 humans in beast with a wretch, to get this the fastest your best bet will be to play casual solo to get the most kills.
Super reload: get the bronze master at arms medal (100 kills with each starter weapon), easiest to make a private match against bots on casual.
Infinite ammo: get 100 combat engineer ribbons (get 5 repairs in 1 deploy), see vid

Do his right from the beginning....

Play Arcade mode though, if you have another player, and you die, the game doesn't stop, unless all active players are dead (or if all four playable characters are "Downed". It's relatively easy to beat the game in hardcore mode in single player. It's stupidly easy to beat the game in hardcore mode in Arcade with someone with decent skills.

The only challenge is the final boss. That's the only place in the game I had to restart more than once. Just practice on that one battle, otherwise it's a cake walk.