What is essential for an IWAD/IPK3?

[tsukiyomaru0]

What lumps and files am I expected to have when starting to craft an IWAD or IPK3 (preferably IPK3 for the sake of practicality)? Also, what would be the ideal IWADINFO for it, in case the one in the Wiki is not viable?

[Gez]

Technically, I think a PLAYPAL, a TITLEPIC (or TITLEMAP, but a picture is more minimal than a map), a MAPINFO lump with GameInfo section, a MENUDEF, and the IWADINFO lump.

You'll get a game where you can get to the main menu and that's all (no actual game content).

[Graf Zahl]

You do not need a MENUDEF and a GameInfo section. For those there's defaults in GZDoom.pk3.

[Nash]

Absolute minimal: PLAYPAL and IWADINFO.

Presentable minimal: check out my standalone game template