Recently Valve updated hl1 and changed something like mp5 spread, NPC turning speed and others. Will it affect hl1 speedrun categories? Will there be new one?
Only Steam category is affected, but even then it’s possible to avoid these changes by downgrading to an older build or using the older GoldSrc Package version (1.36).
So, on this site, will there appear a new one?
Nope. These changes are too insignificant for a new category to be made.