Tactica Online, developed by Imaginary numbers, was a turn-based strategy RPG set in the Renaissance in the age of Leonardo da Vinci. Da Vinci is working on some designs for war machines for the government, and there is an ongoing battle between believers in magic and believers in science over which side holds the truth and which is nonsense. Players take sides in this debate by way of their characters who, in teams of six, must make their way through the game's series of 30-minute story quests as well as engage in regular PvP battles with members of the other side. Imaginary Numbers planned updates to the story content and the game itself every few months.

Both story and combat aimed to be impressive, with over 160 ontainable skills, and a rich storyline involving government conspiracies, secret societies, the Inquisition, and Leonardo's (in reality never made) war machines and tank designs come to life. In addition to lots of possible skill combinations, there were still classes and levels, although victory in battle was a mix of strategy and skill, not just mere rolls.

Tactica was never released. It was quietly canceled in April of 2006.