1. The Symbol Dice
The core conceit of Genesys, like the Star Wars RPGs, is funny symbol dice. These are ultimately easy enough to interpret, but it still takes time....more time than just looking at a set of numbers. The problem mainly stems from density of information; one cluster of dice in a single check will carry a lot of information with that roll, such as:
If you hit or not in combat (or succeeded)
Extra damage done
degree and type of failure/success
If any special success/failure happened (triumph/despair)
If special effects from weapons/tools/abilities trigger
In and of itself, this mechanic works just fine, and in playing through it led to scenarios where the dice helped direct the narrative flow of what was going on to aid in justifying a series of advantage or threats. Indeed, for most events not related to combat or magic casting the mechanic is very straight forward, and the GM can interpret extra levels of success/failure/advantage/threat as he or she sees fit.
Of course, a lot of the game (in fantasy gaming, anyway) does involve combat and magic, which gets to part 2...
2. The Charts
Hidden throughout the book are a metric ton of charts you can use to interpret the dice symbols you may gain during combat, social encounters, magic and other situations. There are about eight pages of these charts, and on the Genesys forums some helpful fans have compiled them in to useful reference charts. FFE hasn't produced a GM screen (yet) for Genesys, and I suspect it's because they wouldn't know where to begin to narrow down key charts on a typical four panel screen; there will be no room for art when they are done!
The charts are what make this game less fun. It doesn't necessarily have to be that way, but what I found was that the following issues arose as a result of the charts:
A. You start referring to the charts as a quick work around to determining what the adventage/threat effects mean. This leads to...
B. Necessarily people recognize that consistency is important so the narrative value of the dice results gets eroded a bit in favor of the obvious best modifiers and results of the dice, which leads to....
C. A narrative die mechanic gets overwhelmed by a sort of rules lawyerism that it can't help, because it provided all the essential rules in the first place.
I started to get really tired of the charts. Not the dice, but the charts. The first few sessions were indeed narratively exciting and indeed even liberating, but by sessions 4-5 we were constantly referencing the charts and all sense of narrative purpose to the dice had been wiped out by the mechanical implementation. YMMV but for me I physically stopped wanting to play the game by this point, and especially no longer wanted to engage with combat.
You might not use Genesys Core for fantasy gaming, but if you do you will be confronted with a fascinating open-ended magic system that seems to encourage creativity....except when it doesn't (especially in combat). The actual play implementation worked best when the player know what he/she was doing, but there tended to be a lot of variables to account for in any given moment, which tended to slow down the magic caster a bit. Not a huge deal (if everyone was on board) but one player who had not had time to learn the system but was trying to play a mage created a great deal of slow down in this process.
4. Combat Overall
Combat in and of itself, charts aside, was fairly smooth and only slowdown came from the pause, usually between 5 and 30 seconds, while people factored in dice symbols. I never got a good idea of how accurately assess difficulty against the party.....foes tended to be either deliberate pushovers or tough as nails but rarely did a PC seem to be at serious risk of death (until one occasion). This led to an interesting analysis of how the system addresses risk of death, and to be honest it's kind of evasive about the entire subject.
5. Everything Else
I plan to run Genesys Core again with an SF setting of some sort, and hopefully they will produce an SF themed sourcebook soon. Unfortunately the sourcebooks are pretty clearly going to be focused on the FFE boardgame worlds, such as Realms of Terrinoth, which I found to be far less useful than I would have liked as a resource to design and populate my own setting. That said, if you like Terrinoth for a world setting, the book provides in spades.
I don't think I could run this system for more than a 5 session run at a time, though. The dice mechanic itself is absolutely fine, but those charts....oh man those charts. I could see getting used to it, but sometimes I end up asking myself, "Do I really want to?"
Especially with Cypher System waiting to be played! But more on that soon....after Genesys wrapped, we rolled some Cypher System PCs up and started a game with that ruleset right away. One hint on my feelings about it: Cypher is definitely game aiming to provide lots of busywork for players while catering to the lazy GM.