The expansion to Armored Core 2 runs on the same game engine as its predecessor but features a number of changes in the way the game is played. There is no trial mission in Another Age that kicks the game off, the player is simply thrown into the world with their AC and their first job offer right there waiting for them. The Arena, which played a significant role in Armored Core 2 has been scaled back a bit, but a fair number of the game's missions involve one-on-one combat with other Ravens in a set-up not unlike Armored Core 2's Arena. Another Age has no expressed plot; it is more a portrait of the life of a mercenary, always bouncing about from place to place and not getting tied down to any particular cause. Occasionally recurring elements pop up from time to time as the game progresses, but there is no defined storyline to the game. While there is no storyline there are over 100 separate missions that make up the mass of the game, the largest Armored Core title to date and each mission plays out in a specific area of the world map screen that would reappear in following AC titles down the road. Another Age is also noted for its cameo appearances. Past enemies from previous Armored Core games Stinger and Nineball appear as bosses in several special missions that are unlocked once you clear all 100 of the game's missions.

Codes
While playing the game enter these codes. After entering them the game will pause; press start to resume playing and the camera will be fixed at the location it has to be set at after clicking the codes.

Hold Triangle+Square+Start - First Person View

Hold Circle+X+Start - Fixed Camera View

Unlockables

Unlock Enemy AC emblems
Enemy AC emblems - Every time you beat an enemy AC in a mission, their emblem becomes selectable in the Emblem Edit samples section. Note, you must destroy the enemy AC for their emblem to become selectable.

Glitches

Change difficulties in mid game
While you cannot change your difficulty setting in single player mode after you start the game, you'll be able to do that in split-screen mode. Just go to ''Split-Screen'' mode and load the AC file that you want to have its difficulty changed. Once the data is loaded, go to ''Options'', look for ''Level'' and change the difficulty to the one you want. Once changed, go to ''Data Save'' and save. When you load the data in single player mode, the difficulty will be set to the one you selected in split-screen mode and you don't have to start all over again. In other words, if you originally set it on hard, then you change the difficulty to normal in split-screen; when you load the data, the game will be set on normal. This is perfect for those who only have one plus file and want to change its difficulty.

Unlimited energy
Press L2 + R2 + R3. A ''Limiter Release'' system error message will appear. During a limited time you will have unlimited energy (about 1 minute). After that minute, an ''OB Down'' message will appear under charging in the upper left corner. It will last almost as long as the previous error depending on the AC core you built, but you will not have any energy. After ''OB Down'' is completed, your AC will recharge and return to normal. .

Secrets

50,000C in 'Attack the terrorists' mission
In the ''Attack the terrorists'' mission in Zearm Desert there is a bomber flying around. Destroy it to earn an extra 50,000C at the end of the mission.

Continue from Armored Core 2
Just go to the load data screen and select a game from Armored Core 2 and you can use all your parts from before.

Once you completed the main set of missions in Another Age, a new area became accessible. Called the Lost Field it offered three new missions against foes from the PSone games: