A 1994 level is a level designed in the style of levels being made and distributed in 1994, the year after Doom was released. As Doom level editing was in its infancy at the time, with tools being primitive and mappers lacking experience, such levels were typically of a substandard nature. 1994 levels may include simplistic architecture, misaligned textures and inappropriate monster usage (eg. multiple Cyberdemons in every level).
Because skill at level editing often comes from experience, many authors go through a "1994 level" stage in their development. Levels designed by inexperienced authors may be referred to as "1994" WADs, even though they are created many years later.