Zero-K is a FREE, multi-platform, open source Real Time Strategy game, which aims to be a dynamic, action-packed, hassle-free experience, full of clever strategies and constantly moving combat. Includes an epic scale, realistic projectile and unit physics, terraforming terrain and hundreds of unique and interesting units.
Wow... what map is that?
This is the top-level view of what looks to be the early stage of a small battle on the "Frozen Fortress" map.
On the very far left corner, you can see someone's geothermal power plant exploding.