alright game, but gets old fast
I like this better than your other games in this series, but it suffers from the same problem of not having much replay value. Also this game is hugely unbalanced.
Basically, spam dinobirds (maybe a few bird men) -> spam roman archers, except when too many air units -> spam medieval warships. And you can beat every single level by spamming medieval warships and only medieval warships. Also you don't even need to upgrade any of the skills to beat all the boards after you get these units (of course skills still help though).
Then the game is even more of a joke when you get the laser spaceship. The only time you may want to change up spamming units, is to spawn some cheap fast units to follow your stronger units into the enemies base - but it's really not required.
I spent too much time on this game myself, but I can't imagine anybody is actually going to play all 100 levels. It just gets too repetitive and boring after a while.