the new 56Nightmare100D2 run plays out of sync

[stanteau]

As soon as he chainsaws the 2 dudes in the beginning it goes terribly out of sync and I use PRBOOM

[Grazza]

Which version of Prboom are you using?

If you are using an old version (e.g. the original Prboom 2.02), then that might explain the problem, as it lacks a good enough compatibility mode for Doom2.exe. Edit: Actually, I've just tested 2.02, and while it does desync, it is on map06, rather than as early as you describe.

If you are using a recent version (e.g. 2.2.6), then maybe you have modified your iwad in some way. Do other demos play back OK for you?

Edit: One last thought. Are you using Prboom 2.3.1, and putting a -complevel in your command line? If so, remove it, and leave it to autodetect the demo format.

[stanteau]

I just drag and drop the lmp on the prboom icon

[Grazza]

My guess is that your iwad (doom2.wad) is screwed, or an old version (1.666). Reinstall it from your original disks, and if it is not version 1.9, then you need to patch it.

You can get the patches here.