after all these years, I've beaten it on very hard (Celts). Swordsman, peasant, peasant, hut, Legend of the Miners, peasant, peasant, farm, swordsman, stable, knight, cowshed, Pantheon of Fat Chickens, knight, max peasants, knight... see if you can take it from there :)
get a crate every game and throw it away unless you pay. Once you use it it takes 8 hours to open unless you pay. Go on missions that give you rewards if you pay 50 creds. Use the little amount of gold you get each game to buy stacks of units that turn into upgrades, which take 2 hours to apply unless you pay. There is then a cooldown on upgrading that unit, which is 50% shorter if you pay. Everything in the game takes hours of time to rotate through this one Upgrade slot. You can get more slots if you pay. Play as one of three factions, randomly, unless you pay. Get a new free crate every few hours, which is reduced by half if you pay. Not only do you pay, but you have to pay monthly. Enjoy using strategy against different units, many of which are only available and therefore counterable if you pay. This game is a cash grab and an excuse to market P2W crates and premium every 15 seconds.
 "50 years (graphical)"){kind=icon}
 "Mini Guns"){kind=icon}
 "Lampshade"){kind=icon}
 "Islandsettler"){kind=icon}
 "Chrome Wars Arena"){kind=icon}
 "Bloons TD 5"){kind=icon}