<GM> 1d64
<&Dice> GM, 1d64: 41
"no moon cycles"
Final Fantasy XI - which was released in 2002 - has moon cycles. Every day of the ingame week, the moon changes colors in a set cycle, corresponding with one of the elemental types in the game (Firesday, Earthsday, Windsday, Iceday, etc). Each corresponding moon cycle makes magic effects of their element slightly more effective, and makes the opposing element slightly less effective.
Here's a simple chart showing all of the game's elemental interactions, and the current moon cycle also plays into it, resulting in, for example, Water element spells being extremely effective against Fire-based enemies when used on Watersday:
https://static.wikia.nocookie.net/ffxi/images/1/1e/Compass.JPG/revision/latest?cb=20050629142300
This is one of several features that add to the dynamics of combat. "It's Earthsday, so this Slow spell is more likely to land super effectively on this enemy, but my Stun spell might be resisted" is one example, and it cuts both ways - all players and mobs alike play by the same rules, since we're all living under the same moon, you know?
But it's not JUST a combat feature.
Each element also has a Crystal type associated with it. Crystals, in short, are common-ish drops that are used for various types of Synthesis, the game's main crafting system. For example, if you kill a Fire-based enemy, you might get a Fire Crystal, which can be used to magically heat up meat and cook it. Wind Crystals can be used to carve wood and bone, Earth Crystals fuse things together, Lightning Crystals split things apart (known as "desynthesis"), and so on.
The day of the week - that is, the current moon cycle -
also
has several effects on Synthesis, depending on which Crystal types you're using on which day, and this means crafters have a lot of dynamics to consider too! Synthing things isn't just a repetitive routine every time you do it - you need to evaluate the day of the week and make a decision accordingly, changing what crafting types you focus on, and the potential results.
Do you have few Crystals and want to make sure your Synthesis attempts succeed more often? Then you need to pay attention to the current moon cycle. Do you have MANY Crystals and want to increase your Cooking or Cloftcraft skill faster, while having a higher failure rate as a tradeoff? You can do that too.
Here's a chart that shows the various interactions, with the outer circle representing "current day of week".
https://static.wikia.nocookie.net/ffxi/images/1/1f/SynthingCompass.jpg/revision/latest?cb=20050526162318
This is all putting aside that moon PHASES - not just the weekly element cycle, but also whether the moon is Full, Half, New, etc, also have various interactions both within the crafting system AND within combat (there's a cool Wolf summon that has different abilities based on the moon phase, for example), but I won't get into all of that here.
The point is, I could talk about how the moon cycles
alone
add to the depth and complexity of FFXI all day long.