So I created a game with some insane-difficulty AI just to watch how they play and they were creating units incredibly fast. Brutes were taking ~6 second to build and archers were taking ~4 seconds to build. I thought the whole praise of the AI in this game is that they do not cheat... Am I missing some critical technique to reducing my units build times or is the AI in fact cheating?

Edit 1:

So I just did some testing to see how much the AI cheats and here are the results:

(all percentages and times are approximate as I just used an iPhone and manually timed each event)

Insane - 80.6% Reduction in unit build time -- 80.8% Reduction in structure build time
Painful - 22.3% Reduction in unit build time -- 16.7% Reduction in structure build time
Tough - 11.2% Reduction in unit build time -- 10% Reduction in structure build time
Challenging - 0% Reduction in unit build time -- 0% Reduction in structure build time
Normal - 0% Reduction in unit build time -- 0% Reduction in structure build time
Easy - 130.5% Increase in unit build time -- 133.3% Increase in structure build time
Beginner - 388.8% Increase in unit build time -- 400% Increase in structure build time

Insane - Archer build time in seconds: 3.5/18 -- Factory build time in seconds: 5.75/30
Painful - Archer build time in seconds: 14/18 -- Factory build time in seconds: 25/30
Tough - Archer build time in seconds: 16/18 -- Factory build time in seconds: 27/30
Challenging - Archer build time in seconds: 18/18 -- Factory build time in seconds: 30/30
Normal - Archer build time in seconds: 18/18 -- Factory build time in seconds: 30/30
Easy - Archer build time in seconds: 23.5/18 -- Factory build time in seconds: 40/30
Beginner - Archer build time in seconds: 70/18 -- Factory build time in seconds: 120/30

Conclusion- It looks like from this simple test that at first glance Normal and Challenging difficulties are the only two AI settings that do not cheat/handicap. I am guessing (and hoping) for now that Challenging AI will just play  better than the Normal AI without cheating, but it may very well cheat in a manner that I haven't observed yet such as resource collection rate,  unit attack/defense stats, etc.

Edit 2:

Draginol (developer) has confirmed that the AI does get a resource boost on Challenging. Thanks!