QStyleNeo1.11.pk3 is the core mod.
QStyleNeo_Zandronum.wad is the Zandronum compatibility patch (currently edits the join game window and nothing else).
QstyleNeo_PVP.pk3 is the PVP patch. It makes weapon spawns static. PVP modes can be ran without this, but it's not recommended.
hfskins6.3.wad is the official player skin pack designed for use with both QStyle and other sister mods.