Coping with the Blurring within Game Engines

I've had a lot of fun over the last few years playing both 2d20 engined games from Modiphius, and Year Zero Engine (YZE) games from Fria Ligan. However, this does present a challenge. I find that the more of the games that I've played, the more confusing I find them (especially if I am playing they in close proximity). This is particularly bad with 2d20.

I find that the problem is that the core of the game remains the same (roll 2d20 under an attribute and skill, build & spend momentum or roll a pool of D6s looking for at least a single '6' for success) but all the parts around it have been heavily tweaked to tailor the game to the setting in use. You can have similar mechanics in different versions of the same system that are driven by different meta currencies which are called different things and work in subtly different ways.

I know that this isn't just my issue; I've had the same conversation at conventions with folks, most recently during John Carter of Mars (2d20) at North Star. The YZE game I played at the same convention - The Electric State - was less of an challenge, as the mechanics were very stripped back.

I've reached the point that I'm actively ignoring any new 2d20 games that come out because I just don't want to deal with this blurring of mechanics between systems. I suspect that the copy of Cohors Cthulhu which is due to march into my house sometime this year may just be sold on unplayed.

I think that there could be a simple solution; one that could easily be done by the publishers or the fan community. Both of these engines have SRDs (system reference documents). I'd find a simple one page overview of how each of the games differs from that SRD really useful. It doesn't have to detail all the mechanics, just the key changes. That would make it a lot easier as a player and as a GM who needs to guide players through the differences in the game they're running.

Anyone else think this is a good idea? How do you cope with playing multiple variants of the same system?

20 May 2025

Postscript

As I took the picture that heads this post, I realised that I've quietly got rid of a lot of my 2d20, whereas I still have all YZE games I've ever bought. The only 2d20 game I'm missing above is Conan (which is in the to-sell pile, to be replaced by Barbarians of Lemuria). I've sold off Homeworld, Achtung! Cthulhu, the first edition of Star Trek Adventures (twice) and John Carter of Mars. I actually have more YZE games, but they aren't as quickly accessible; Vaesen, Coriolis, Things from the Flood, Twilight 2000, MYZ: Mechatron and Forbidden Lands. It looks like I've subconsciously made that decision between the two engines. Strange, as I do like the way that 2d20 plays.