Real-time tactics (RTT) is a subgenre of tactical wargames played in real-time, simulating the considerations and circumstances of operational warfare and military tactics. It is differentiated from real-time strategy gameplay by the lack of classic resource micromanagement and base or unit building, as well as the greater importance of individual units and a focus on complex battlefield tactics.
A supply ship with destroyer escort in Nexus: The Jupiter Incident.
Turn-based tactics (TBT) is a video game genre of strategy video games. They are turn-based simulations of operational warfare and military tactics in generally small-scale confrontations as opposed to more strategic considerations of turn-based strategy (TBS) games. Turn-based tactical gameplay is characterized by the expectation of players to complete their tasks using only the combat forces provided to them in a generally realistic manner.
Individual units are commanded to perform military tactics such as an ambush. Screenshot is from The Battle for Wesnoth.