SpDemAc is a map set for shareware Wolfenstein. It was released on April 6, 1999. Exact authorship is unknown.
A Read Me file followed the download, which was authored by Brian Lowe. The main purpose of this set was to give users of Acorn/Archimedes computers a chance to play the demo version of Spear of Destiny; hence the presence of the first two Spear levels in this set as levels 1 & 2.
This is likely also alluded to in the title; Spear Demo for Acorn.
The two other levels, 3 and 10, are relatively poorly made and quite difficult.