Thanks for the kind words. I submitted it yesterday to a jam, so haven't had the time to do the final polish. Will try to add that tonight :)
The controls are:
Mouse:
- Right click for unit selection.
- Left click to Move and Interact
-Middle mouse button to pan
Keyboard:
WASD - Pan
Shift - Pan with the mouse
As for the crystals the 2nd and 3rd level make their purpose clear ;)