Are we allowed to run the original PC version on an old PC for the PC category?

As long as you’re following all of the rules for the PC category I don’t see why not? I figure there would likely be a lot of crashing though with how old it is.

And my brain is so fried from work that I just now realized that this isn’t the RE1 forum XD I need sleep and a break from the heat.

Would be great fun to see and play the proper OG PC version on an old system, used to know someone back in the day with RE1 on PC, what a beast

As the rules state the PC category is for Sourcenext only, there's multiple reasons as to why we have this rule.

Firstly compatibility issues, the PC ports of the classic RE's were never the best even way back when they were released, almost all early versions of the game have crash bugs in the lab specifically for Claire A and both B scenarios while entering the monitor cutscene, on all versions only Leon A was the only scenario without any issues, it's still possible to complete the other scenarios if a save file was made.

Secondly is the In game timer, it works differently across some versions, some pause the IGT on black screens, for example entering and exiting the inventory, before or after a door transition. There was also a version that counted credits towards the IGT.

Before we had the Rebirth patch I spent countless hours researching and playing different versions of the game to try and find a version that could co-exist with Sourcenext because of all the compatibility problems we had with it but no luck. I tried every PC version I could get my hands on listed here https://www.crimson-ceremony.net/lostreleases/regame/re2.php And none of them matched up to the point they could co-exist on the same leader board.

FYI the best release of the game aside from Sourcenext is "Sold out extreme software" version, it's an Eu version with very little problems the IGT is just slightly different to Sourcenext and obviously it's English text so much slower.

Ahhh nice one! I didn't realise there were so many different versions of the PC port. The one that caught my attention was a copy of Biohazard 2 Sourcenext which i found the disc for the PC. I was just assuming that there were only a couple of different PC versions without thinking that all the IGT is all counted differently depending on what version you are playing. Thank you for the info, I've learned something from this, much appreciated :)