It appears that Drs. Jones and Freeman account for the arch over the hagioscope at St. David's by saying, though without citing authorities, that there was a door there originally.

[…] a restraint, Though all the world’s vastidity you had, To a determined scope.

While there's a decent variety of enemy types in the game, those same enemies also tend to get palette swapped as the game progresses.

Intralingual translation involves adapting a text to a new purpose in the same language.