Harvest: Massive Encounter

Harvest is a real time defense-strategy game from the independent Swedish developer Oxeye. Harvest's premise is that you colonize one of 3 planets: an arid one with craters, an arctic one, and a temperate-climate one. This gives you a reason to build a base with the purpose of defending yourself from incoming aliens, some common to all the planets, some specific.

Although you can only build a handful of buildings and no units whatsoever, there are various in-depth strategies to be explored, two resources -- energy and minerals -- and some variety of configuring the defense structures.

An innovative concept brought by the game is handling one of the resources - the energy. It doesn't show as a number in the interface, you can see it as sparks flying between energy link structures. This brings an extra challenge of storing and distributing it optimally to consumers.