Important change: NPC invaders

Suddenly, the world of Screeps has become less safe. It seems that intensive mining and industrial development in once virgin regions shattered the environmental balance and enraged mysterious forces we know little about. The time of peaceful travel came to an end, and since now, everyone should keep on the watch.

NPC Invaders

Every room where energy is mined has an inner counter at approximately 100,000 units of mined energy (plus some random variable). After this counter times out, a new game-controlled creep appears at one of the room exits with the goal of hunting your creeps. It will not touch your spawns, but if a structure gets on its way, it will try to destroy it. This creep can use attack, rangedAttack, and dismantle. It is unable to move between rooms. 

An important feature of these creeps is that they can appear only at exits to neutral rooms. If the target room is under your (or someone else’s) control or it is a reserved room, an invader creep will never appear at this exit. If all exits in the room are of this kind, invaders cannot appear at all.

There are two types of invader creeps:

  • Light creeps that appear in neutral, reserved, and claimed rooms under level 3.
  • Heavy creeps that appear in claimed rooms level 4 and above. 

UPD: There is now a chance that you will get not only a lone invader, but a whole company of them. Learn more from this article.