I've got all of my demos from my run and want to record them for my yt. I've done this with tf2 demos, using lawena. I'm 99% sure you can't use lawena with Portal. What's a good alternative for doing so? And does it have a queue option? (So I can add up all of my demos and record them)
use the command startmovie and run the demos using playdemo
This is a helpful guide i used when making a segmented run https://wiki.sourceruns.org/wiki/Source_Video_Creation
The only way to do it clean is to do what hat said. The clodo strat is that you record your game with OBS/XSplit/Mishira/Bandicam Playing many demos at a time isn't something I would recommend.
An update has been released for SST that adds the command sst_portal_resetisg. This command removes Item Save Glitch and is to be used in place of restarting the game. This is a temporary solution while a more robust and legitimate one is developed.
The reasoning for allowing this is to make the ne