The humans rely on technological upgrades and their units includes elves and dwarves. The orcs are joined by trolls and wyverns. The undead can raise corpses after a battle to gather more units. The night elves are a tree-based race whose buildings can root and uproot to move around the map. Each side has unique classes for their heroes, who can learn special skills and abilities as they go up levels and are carried over from mission to mission.
Heros also acquire magical items.
Blizzard isn't exactly known for innovation and this is no exception. Battlecry', 'Yeah, they did that in Kohan', or 'Yeah, they did that in Earth 2150'. But Blizzard is living proof that innovation is overrated. Warcraft III looks great, the team has some clever ideas for their four unique races, and I have every confidence that they'll deliver a fine RTS that will break sales charts if not paradigms. The Blizzard hallmarks are all there, from good voice acting to attention to detail like water rippling as characters step into it.