Gatling Gears

There are three survival arenas to choose from and in my opinion, the first one (Arena A) is the easiest. Obviously, select Easy difficulty for this achievement. You lose a life when your whole health bar is depleted but green repair powerups will replenish some health so be sure to pick these up. These and other powerups appear randomly around the map so keep an eye out for them. A good strategy sometimes is to wait near a health or weapon powerup so that you can save it until you really need it, but keep in mind it will start flashing and disappear after a short while. Also, be sure to make use of your missiles and grenades since you have an unlimited supply (however they need a short time to recharge). Your shock bomb (the Y button move) is only a one time use so use it only if you are really in trouble. Another thing you need to know about this particular map is that you can lose in another way. If too many TNT mine carts destroy both of the big structures at the bottom left and bottom right of the level, you will fail the survival mission. When you see a cart, you need to make that a top priority. You won't fail if just a few make it there but you need to try to defend the structures as much as possible. Don't worry though, other enemies and your weapons can NOT destroy the structures. You will need to survive 10 waves for the achievement to unlock. One more thing, this achievement can be done in solo or co-op (I did it in co-op and would definitely recommend it).