/vr/ - Retro Games

>Look up OST of a WAD I really like on youtube
>Read the comments out of curiosity
>Some guy says: "one of the best megawads I've ever played"
>Oh cool nice taste ma-
>"Especially in combination with complex doom v26.a2 and LCA 1.5.9"

Why are people like this

>>6329393
Hey Doom nerds, I have a question.

I came across this map called "Holy Hell Revealed" (since it was mentioned by >>6329609 ) and a TAS UVMax run for it.
https://youtu.be/Yw9pz5WH_T4?t=5190

However, if you download the demo from the video description and try to play it back yourself, the demo desyncs at around the ~86min40secs time mark. The TXT included with the demo says:
>This demo plays back correctly only on 64-bit builds produced with clang (a bug in the source code or compiler). The desync happens after 86th minute. So you need to compile PrBoom+ with clang and the build must be 64-bit for the demo to play back correctly.

So my question is - why is that? We're both using -complevel 9, so why would it matter what version of PRB+ you're running it on? Isn't the whole point of demos that they're supposed to work regardless of the version of the sourceport you're using?