General

Escape - Pause game
F12 - Screenshot
MouseWheel - Change player camera zoom level by 2.0f (+/-)
Left Shift - Speed up player camera by 250u/s
Control + + - Zoom in
Control + - - Zoom out

Units

LMB - Selects unit
Ctrl + LMB - Adds unit to group of already selected units.
RMB (Unit) - Set unit movement destination.
RMB (Building) - Set unit rally point.
Del or End - Deletes selected unit(s).