In addition to the core Mass Recall mod, you can download Enslavers Redux, made by modder OmegaWeaponX. Version 8.0 of the project was released this week, as posted on SC2 Mapster by one of the project leads, karlprojektorinski, containing 59 maps from Brood War, three that were removed in some way, and another six that came in a 1998 demo. According to a long-running thread on the Team Liquid forums, all the progression and dialogue from the original StarCraft has been carried over and preserved, but the difficulty curves have been altered to feel more like the modern strategy game experience.
StarCraft: Mass Recall is a fully playable recreation of StarCraft and StarCraft: Brood War, in StarCraft 2, and you can play it all for free. In an incredible piece of StarCraft-ception, some dedicated fans of the space game have remade the first in its own sequel.