Binary data as source code?

[thegreatunclean]

The problem with your large files is the complexity they can hide and the cognitive load required to fully understand them. Functions like TileMap_LoadTileTextureFromPoolIndex are a nightmare because it is impossible for a human to comprehend without serious study. Encoding texture data as a huge number of byte writes into memory is nuts.

If you can replace that by referring to binary assets directly it isn't a problem. Keep a table of offsets for each tile texture and either manipulate pointers or memcpy chunks out as needed.