For Phase 1 and 2, do not have a multiplayer demo in the DEMO1 slot.
Vanilla Doom (and some source ports) do not allow using the “load
game” option while in a network game, and network game demos count as
such.  The other three demo slots are fair game, since they do not
near-immediately block out the load game functionality when starting
Freedoom.

FreeDM is exempted since it is not intended to be a single-player
game.

Current demos recorded:
Phase 1:
DEMO1: C1M4 single-player by Erick - v0.12
DEMO2: C2M3 single-player by Erick - v0.12
DEMO3: C3M3 single-player by Chungy - v0.12
DEMO4: C4M6 single-player by Erick - v0.12

Phase 2:
DEMO1: MAP15 single-player by Erick - v0.12
DEMO2: MAP10 single-player by Erick - v0.12
DEMO3: MAP02 single-player by Obsidian Plague - v0.12
DEMO4: MAP26 single-player by Chungy - v0.12

FreeDM:
DEMO1: DM21 by Xindage, Chungy, Erick, and Xer - v0.12
DEMO2: DM06 by Chungy, Xindage, and Erick - v0.12
DEMO3: DM18 by Chungy, Xindage, and Erick - v0.12
DEMO4: DM09 by Chungy, Xindage, and Erick - v0.12