The demo is included inside the ltm. You may need to rename it to .tar.gz to extract it.
Youtube encode:
! Version info:
libTAS version: 1.4.1
! Annotation info:
{{To sync:
1. Compile SRB2 2.2.9 with line 108 commented out in src/sdl/i_system.c (#define NEWSIGNALHANDLER)
More information: http://wiki.srb2.org/wiki/Source_code_compiling/Makefiles
2. Download CL_FlyingSonic-v2.3.pk3 and V_customsave-v1.soc from the SRB2 message board to your SRB2 home folder (by default ~/.srb2)
https://mb.srb2.org/addons/the-fsonic-double-combo.622/
https://mb.srb2.org/threads/custom-gamedata-allows-you-to-create-save-files-with-addons.27064/
3. Download the gamedata.dat from speedrun.com/srb2 to your SRB2 home folder and rename it to custom_gamedata.dat
https://www.speedrun.com/resourceasset/ou09x
4. Run echo "addfile CL_FlyingSonic-v2.3.pk3\naddfile V_customsave-v1.soc" > autoexec.cfg in your SRB2 home folder
Using autoexec.cfg starts the game faster than the -file command line parameter
5. Start the game with the -skipintro command line parameter}}