Illyriad is a free to play, browser-based MMORTS game set in a fantasy world that is home to a large number of countries and warring factions. There's no download required, players just simply sign up for an account and they're able to play straight away.

The most unique aspect to Illyriad is the ability to play the game your own way. Many browser-based MMORTS titles are very restricting, forcing players down a combat route. Instead of just declaring a war, players are offered different avenues of attack and support. They're able to simply attack opponents, attempting to whittle down their army with a series of small assaults, or they can select Raid to try to decimate their opponents in one swift attack. Other options include taking your opponents military out but keeping the town intact, allowing you to occupy their city and claim the resources and units leftover. The final option is to lay Siege to a town, forcing your opponents to make a move as you cut off their supply chains and military support.

As well as straight up battles, players can also utilize a number of underhand techniques to help win wars. They can choose to attempt to get a spy to infiltrate enemy strongholds, providing valuable information such as unit types and structural weaknesses. Spies can also steal resources and technologies from other towns, as well as planting false information about your own city. The other 2 options, which are far more direct, include Sabotage and Assassination. Sabotage allows players to disrupt their opponents constructions or even halt training of their units. Assassination gives players the opportunity to kill a figurehead in their opponents city, decreasing morale.

Illyriad includes a huge research and development system, with players being able to upgrade units and buildings. This system is constantly updated and currently includes almost 300 unique research options.