The "New AI" introduced in the HD era received tweaks to be more competitive without cheating, making single-player skirmishes more rewarding.

The "Portable" tag usually means the game has been configured to run without a formal installation process. This offers several perks:

The ultimate defensive pick. Their cheaper counter-units (Spearmen, Skirmishers) make them nearly impossible to break in the early game. Performance Tips for HD Edition