Ultima6, Lord British's Castle

You can shoot rockets through the walls.

Rather than being offensively bad, more of the traditional bad map, more just not good. The map is almost empty, with next to no enemies and way too many power ups, I spent most of the map on 200 Hp + Armor, map just seems incredibly amateurish rather than anything else, with over spaced rooms, obvious secrets, light clipping errors and 1 pixel thick walls, combined with an incredibly simplistic pattern featuring mostly the same wall design and few varying objects, resulting in an overall lack of theme. Requires greater decoration and substance in general, with some rooms just seeming random, leading me to suggest further planning.

Overall, a lot of work required here...

Huge map with a bunch of huge empty rooms, no indication of what you are supposed to do, all weapons except BFG, piles of powerups, 22 low level monsters and one lonely Baron. Yeah, no. Pretty much a wasted download.