The Celestial Impact Website offers version 1.00 of Celestial Impact, as this free multiplayer-only first-person shooter has emerged from its extensive beta test. Here's word on the game and its use of deformable environments:

Celestial Impact is a team based multiplayer first person shooter (FPS) set in space on an asteroid with spherical gravity. What makes this FPS really special is that the landscape is fully deformable in all directions. Each player is equipped with, apart from a commonly seen weapon arsenal, a special tool called Dirtgun. With the Dirtgun, players can add or remove terrain during combat as they see fit, simply by aiming and firing the dirtgun. Depending on the chosen action, this will either add or remove a chunk of dirt from the landscape.

Ran in to a wall that is too high to jump over? No problem, just build a slope and walk over the wall, or perhaps dig a tunnel going under it. Need a breather from intense combat? No sweat, dig a cave and go hide inside. Since the layout and flow of the landscape in the maps depends on the player’s actions, playing a particular map will be a different experience each time.