"Colony 21" is an SMS/TV war game that employs mobile SMS messages to control air-strikes, grenades and laser defence systems.

The bunker represents the last stand of the colonists, which must be protected. If it is taking too much damage, the user must repair its shield and structure. If the bunker is protected for long enough, a specialist is able to release a fierce virus into the machines central unit: the 'brain central.' If the bunker takes too many hits, the battle is over. The player wins points by destroying the invading space robots and matching their score against other players.

Multiple game players can join and enter the action. Their movements are controlled by sending Premium SMS to a TV Station server. Players send SMS messages with the co-ordinates for firing weapons. Messages are displayed in real time on broadcast TV. Users type a nickname and "G 120 50" to fire a grenade at a direction of 120° with 50% power.

"Colony 21" shows how iTV producers can create game concepts that are commercially viable.