3rd Edition is the most divergent rule set for WFRP. It used set of bespoke success dice rather than the d100 system of the other editions, similar to those used in Fantasy Flight Games Star Wars RPGs and their Genesys setting agnostic RPG rules. I find that type of resolution system a bit marmite – some love the extra narrative flourishes it demands, others really hate it. Worth pointing out that you will also struggle to find 3rd Edition stuff. FFG gave up/lost their GW license, so there’s not been any hard copies of any material printed for some years, and I’m not sure if anyone has grabbed the rights to sell any digital products.

2nd Edition isn’t that different from 1st Edition, with some tweaks made to have a more balanced system. All the books can be grabbed in digital format from Cubicle 7 (for both Editions I think). 2nd Edition brings in the magic system fully, has more combat options, has basic skills, and skills based off characteristics. So if you really enjoyed 1st edition, I think you’ll get along well with 2nd.

4th Edition was a step back to the d100 system after the success dice pool of 3rd, but made a few changes to 2nd Edition, mainly in an attempt to streamline combat and character advancement. Whether it is an improvement on 2nd Edition, I’m undecided. I liked the much more crunchy combat of 2nd Edition, but quite like the character development system in 4th.

Most of the material from 1st, 2nd and 4th Editions can be cross-compatible with a little tinkering, particularly 2nd to 4th.