The gameplay is famously complex due to its massive unit variety. Success requires mastering a deep counter-system:
Yes, but it is slow. A standard skirmish against the AI can take 2 hours. The pathfinding for units is frustrating (cavalry get stuck on trees). The graphics are dated.
Losing a hero is a significant blow, forcing players to be cautious with their leadership units rather than treating them like disposable soldiers.
This design forces the player to scout. Building a massive army of tanks is useless if the enemy has built a screen of anti-tank infantry. Success in Empire Earth is rarely about who has the biggest army, but who has the correct composition.