It looks like the Age of Empires of old, but free-to-play has ruined a beloved game.
Instead of unlocking everything from the start in a civilization as in previous AoE games, everything is locked. You only unlock higher tiered units, upgrades, and buildings as you level up in the game, in typical RPG fashion. The problem is that this formula doesn't translate well to AoE online. The game is incredibly unbalanced to the extent that it is nearly impossible to complete a campaign without purchasing an army. Certain missions require a specific unit to complete, and if you don't have that unit, you must grind until you can purchase it.
Let's be clear: had AoE Online been a onetime purchase game, I have no doubt the reviews would have been phenomenal. The problem isn't even that they are charing money, obviously a game can't be free. My gripe is with the amount of money the game is charging. $20 for a premium civilization is highway robbery. If you want this game, you have to pay, and the price they're asking is nowhere near worth it.