Gave it a five but changing it to a 4 because it's flagging. Just done level 40 which is 14x14, 14 sources, 6 links and 2 dummies. And so onto level 41 which is the same !!?
With 160 levels to go the difficultly has levelled off. They just take longer each time they get a bit bigger, and offer no new new challenge, except to your eyesight and patience. Excellent concept, very nice design but should have far fewer levels.
Finished. Still a 5 for me as yes it's slow and repetitive to upgrade all the races but you can never switch off, you can screw up easily if you unlock things in the wrong order (as I almost did with the Orcs) and the last three levels make up for it. Kept me playing.
One bug: levels 17 and 18 said 'Cleared 1' but were red before I did them. I did not notice it earlier. Started playing when it was at 1.12
Doesn't work for me - it doesn't detect the control button, though the Keyboard Viewer at the same time show's it's being pressed and detected by the browser. OS X 10.5.6, Safari 3.2.1
 "Colourshift"){kind=icon}
 "Strategy Defense 4"){kind=icon}
 "Epic War 2"){kind=icon}
 "The Codex of Alchemical Engineering"){kind=icon}