- Estimated achievement difficulty: 8/10 [Achievement Difficulty Rating]
- Offline: 99 
- Online: 1 
- Approximate amount of time to 1000: 200+ Hours [Estimated Time to 100%]
- Minimum number of playthroughs needed: 1
- Missable achievements: None
- Does difficulty affect achievements: Yes
- Unobtainable/glitched achievements: None
- Extra equipment needed: None
- DLC: Title Update
- Difficulty: 7/10
- Time to 300: 50+ hours
- Unobtainable: None
Welcome to Age of Empires II Definitive Edition, one of the most highly rated and influential strategy games of all time. If you like strategy games it definitely should be part of your collection. That being said it is likely to take a very long time for you to obtain all the achievements in the base game, and even more for the added new expansions. It's a credit to just how good the game is that the player base is still so large and new expansions are still being released over 20 years after the game's original launch.
Your first step should be the campaigns - all of them need completing and most have at least one or two miscellaneous achievements tied to a specific mission. Make sure you check the guide for each campaign so you don't miss out and end up having to replay missions. If you've never played the game before definitely start with the William Wallace Tutorial Campaign as it will get you used to all the controls, etc., and teach you a good deal about the game.
The campaigns can all be completed on the easiest difficulty with the exception of one mission required for Roar like a Lion (20G) and is where a majority of the time playing the game will be spent. Each one could take you around five hours, perhaps longer, and there are 26 in total.
Once you have completed the campaigns you should move on to playing skirmish matches to mop up miscellaneous achievements you may have left to obtain such as the win with a specific civilization ones for the Age of Empires (5G) achievement and beat an Extreme AI for Prominent Player (20G).
There is only one multiplayer achievement in the game but it isn't easy: Masterpiece (10G) requires you to beat three other people by yourself. It's recommended that you get a group together for this one.
By now you should have most if not all the achievements. Be sure to check the guide for specific ones you're missing. This may involve replaying campaign missions or be easily completable in custom skirmish games.
A great game and one that's highly recommended, but be warned that cheats disable achievements. As a result, the full completion of the base game is likely to take considerable time, with the additional expansions only adding to that. Most of the achievements are relatively straightforward; however, there are a handfull of campaign ones that will challenege even the best of Age of Empires players.