The initial release of the premium expansion pack brings two of the eight new downloadable maps being offered up for the game. Map Pack 1 includes ‘Service Interruption’ and ‘Height of Confusion’ maps, with alien advantages for the first and endless possibilities for strategy on the ladder.

Happily, the content runs just $1 (80 MS Points) and will see a release every Wednesday this month except June 30. So one down, three more to go!

From the description:

The first premium expansion pack for the award-winning Defense Grid: The Awakening arrives to Steam today in the form of Defense Grid: Resurgence – a series of eight new highly polished and balanced maps from the original creators of the definitive tower defense game.

For four consecutive weeks starting on June 2nd, a new pair of maps will be released each week providing new environments and strategic experiences, requiring new ways of thinking to beat back the aliens and protect the cores.

Today’s Map Pack 1 release includes two new challenging environments – Service Interruption and Height of Confusion. An obstructed road to the core housing gives the aliens a significant advantage in Service Interruption. Choose your towers wisely! Height of Confusion has a wide open surface, making for endless possibilities! Build anywhere you want in your defense of the power cores!

With the drop, the newly priced PC version falls in line with the Xbox Live Arcade offering, which is available for 800 MS Points ($10).

For those who’d like to check Defense Grid out before they buy, a demo is available for Steam users to try anytime.