The missions can be played offline or on, though the latter requires additional steps.
The overall difficulty was significantly increased to compensate for the better UI and make the missions more challenging. The gameplay and UI improvements of StarCraft II, like unlimited unit selection and smartcasting, are retained.
The missions use the same tech tree and objectives as the original, although there exists the selectable option of using Brood War units in the original campaign. The mission briefings mimic the originals in appearance and content.