The gameplay video profiles Gandalf and Gollum, both of whom are playable characters in the game's multiplayer objective-based matches.
Gollum plays as a quick character for hit-and-run tactics, while Gandalf is an enchanter capable of withstanding and dealing out heavy damage with his spells.
There will be a total of 20 guardians from the popular fantasy franchise, including Galadriel, Legolas and Gimli.
The game will centre around multiplayer online battles, where players attempt to conquer opposing fortresses using the abilities and skills of their guardian characters.
Announced at this year's E3 Gaming Expo, Guardians of Middle-Earth is being developed exclusively for consoles by Monolith Productions.
It is due to launch on Xbox Live Arcade and the PlayStation Network this autumn.
Watch the debut gameplay trailer for Guardians of Middle-Earth below: