I tried to make a custom ingame.lvl and retextured the health bar texture. I put the ReadDataFile("DC:ingame.lvl") line before the one without the DC, munged, put the ingame.lvl in my map's LVL_PC folder, and played it. In-game, there was no change (I'm certain this procedure works, I've done it before on other maps). I removed the second ReadDataFile line and kept the DC: one, and I get a crash with the following error log:
What's wrong now? I kept the original ingame.req, so everything should have been munged, including the human anims.

I'm not sure but try lowercase dc: instead and add back the original ingame.lvl line as well.

I'll try it, since it's something to do, but every other time I used DC: (including for ingame.lvl tweaks) uppercase has been fine. It's an odd case of LUA being case-insensitive.

First of all, your add-on ingame.lvl should not be loading the entirety of the ingame.lvl - if it is, that should be fixed. If it's not, that's your error - the entirety of an ingame.lvl has to be loaded.

Secondly, your munged ingame.lvl won't (I believe) include everything that's needed to run the game by itself, even if you do munge the entire unmodified ingame.req.

It would help if we could see exactly what's being changed and how it was.

I don't know if you have been following RepSharpshooter's HUD tutorial, but if not you may find it a boon to do so:
http://www.gametoast.com/forums/viewtop ... &sk=t&sd=a

I've seen the HUD tutorial. What was changed was hud_jetpack_and_energybar_fill.tga in dataTTM/Common/interface. I've reskinned it as I would reskin most other textures. I reference it under a "texture" section in ingame.req, put the original ReadDataFile("ingame.lvl") line back in the LUA with a DC: version before it, and munged with the Common box checked, nothing else. Then I copied ingame.lvl from dataTTM/LVL_PC into TTM/data/lvl_pc.