suggestion: an addon that makes it so combine balls leave those scorch marks on things they hit like in portal 1

Huh, you're right

This fix already exists on the Workshop; https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2893450274

same

You know, I never even noticed that the texture was different. Still, I'm sure quite a lot of people will appreciate this simple fix (though I'm assuming it'll have to be disabled when not playing on Portal maps for the texture to be the HL2 version again).