I'll have to agree with others that it lacks some more documentation, and that the difficulty curve is not good, but for a jam game this is a pretty big accomplishment! Graphics are great, SFX are pleasing, and John never fails to deliver appropriate theme with his compositions. This Age-of-Empires-like atmosphere is what truly won me. It really felt like I played that game, only with cactii. :D
Can't wait for next Age of Cactii.