Ascension takes place in a Russian Space Station at night. The map will be in black and white until you turn on the power. You can find the Power Switch on the top floor of the main building. You start of the game at the bottom floor of the main building.

Along with Zombies are special enemies called "Space Monkeys." Space Monkeys are pretty fast and extremely hard to hit because of their size. The higher the round, the more Space Monkeys there will be. They will flood into the map like ants. Space Monkeys come every few rounds after a Perk is bought. After you kill them all, they will drop a Max Ammo Power-Up, just like Hell Hounds. Space Monkeys don't attack players right away. Instead, they will latch on to Perk-A-Cola Machines and take your Perks. They only attack the Perk-A-Cola Machines you and your team bought from. It takes a few seconds, but the perk will be stolen after touching the machine. If you can kill all of them before any of them touch a machine, you will earn a brand new Power-Up which gives you and your team a random Perk-A-Cola.

The Mystery Box is available on this map and will always start right next to the Power Switch. After a few uses, the Mystery Box will move to a new location on the map. Look at the TV near the Mystery Box spawn locations to see the location the Mystery Box is currently at.

Two new weapons are added to the Mystery Box. The weapons are called The Gersch Device and Matryoshka Dolls. The Gersch Device replaces your Special Grenades and sucks zombies in like the Ghost Busters. The Matryoshka Dolls replace you Special Grenades and explode multiple times like a cluster bomb.

Two new Perk-A-Colas have been added to Ascension: Stamin-Up and PhD Flopper. Double Tap Root Beer cannot be found on this map, which means there are five Perk-A-Colas in Ascension, yet only four can be bought at a time. Stamin-Up allows you to run for a longer period of time. PhD Flopper prevents you from taking any fall damage or explosive damage, you can even cook a grenade in your hand. If you dive off of a high spot, you will cause a small explosion that can kill any zombies around.

The Pack-A-Punch Machine is back again, but it requires a few steps to gain access. First, you must use the Lunar Lander from all three locations to the main building. Second, you must press a launch button right next to the Power Switch, this will launch the missile from the launch pad. Now the Pack-A-Punch area will be open underneath the launch pad. The area will stay open for the rest of the game.

Power-Ups that are unique to Ascension include:

For a list of Power-Ups available on all maps, view the Power-Ups page.

Along with the color, the power activates all the Perk-A-Cola Machines, Traps, and a new transport called Lunar Landers. The traps on Ascension include Fire Traps, which act exactly like the Electric traps from past map, and Automatic Turrets. The First traps cost 1000 Points while the Automatic Turrets cost 1500 Points. Each use lasts 30 seconds and has a 90 second cool down period.

The new Lunar Lander transport act a bit like teleportation pads. There are four platforms around the map which holds the Lunar Lander. The Lunar Lander starts in the same room you start at. After the power is activated, you can call a Lunar Lander to one of the other platforms. If a player is on the Lunar Lander while it's being called, they will be transported across the map on the Lunar Lander. If a player doesn't call the Lunar Lander to a new location, you must buy a trip for 250 Points. The Lunar Lander will always lead back to the starting position if you buy a trip. After the Lunar Lander reaches it's destination, you must wait 30 seconds for the Lunar Lander to refuel before using it again. If you stand underneath a Lunar Lander while it's landing, you will be downed instantly.

Continued here:

Ascension - Call of Duty: Black Ops Wiki Guide - IGN