The cost progression of the different units is very poorly balanced. The increased cost (both food to produce and gold to unlock/upgrade) of the 'more powerful' units is way out of proportion to their tiny increase in usefulness.
If you can handle it, these games are actually quite easy if you cross your eyes and focus on the superimposed images. All of the differences stick out because they're the only parts of the picture that aren't in focus. 805 on my first try btw.
 "Paladog"){kind=icon}
 "ISIS (challenge edition)"){kind=icon}