Quote: "They definitely did edit the source."
Sorry to break the news to you here Inspire but I'm afraid this isn't the case. You don't have to take my word for it though, check out the E.L.E second video thread (sticky) in the showcase forum. Here is an extract
Quote: "- No, We did´nt modify code, but... I think that we modified all the rest, for sample, all shaders of game are of creation of one's own like ELEbump, ELEwater, ElErefract, etc... We modified the system of creation of scenarios, hundred of scripts, etc..."
You'll see if you visit that thread I have mentioned you as this hadn't been made clear from the first thread which you posted in.
http://forum.thegamecreators.com/?m=forum_view&t=111090&b=25
Source code edits tend to be a nice way to justify things which we don't immediately understand. It's the shader files themselves which have been modified / re-written to produce more stable quality graphics in E.L.E not the engine itself.
As for the animated menus, looks like spending some time looking into how a HL2 3D scene is produced would be a good place to start.
Best