Hidden Path Entertainment has launched a Kickstarter project to fund the development of an expansion and sequel to its popular tower defense title Defense Grid.

The campaign's $250,000 goal covers the cost of creating Defense Grid: Containment, a planned eight-level expansion for the original Defense Grid game that continues the series' storyline and leads directly into a sequel.

The sequel itself, however, won't come cheap. At $500,000, Hidden Path will develop a new engine and remaster the original Defense Grid's content, adding a co-op multiplayer mode. If the campaign exceeds $1 million in pledges, Defense Grid 2 will be funded in full.

Backers who pledge $15 or more will receive a copy of the original Defense Grid immediately, along with all future content, including the Containment expansion and Defense Grid 2. Other backer rewards include beta access, posters, and customized phone answering messages from the game's voice cast.