I'm going to write a little about pacing mechanics, although to be honest I'll probably make a video on this topic once I've worked out the kinks.
Pacing mechanics are gameplay that exists only to keep the game flowing at the right rate, and with the right traction. In theory you could argue that all gameplay is like that, but pacing mechanics are specifically for that purpose rather than to be entertaining, challenging, thought-provoking, etc.
An example of this would be in an Animal Crossing game, where you can only harvest things once per real-world day. This gives the player a specific amount of that rewarding task each day: enough to call the player back (traction), but only a small amount, so they're encouraged to do other things once they're engaged (flow).
There are three basic kinds of pacing mechanic, as far as I can tell.
The physical play mechanic, like in the Animal Crossing games.
It lures people to log in each day, or on specific days, or in specific places. For example, Pokemon Go rewards players for going to new real-world locations, or physically meeting up with friends.
This is a bit different from the kinds of energy play you often see in mobile games. Rather than providing traction and flow, most energy mechanics simply let you play until you suddenly can't play any more... unless you pay money. The traction and flow elements may still exist, but they're weak, because they're not the point.
The structured play mechanic, where players are given specific, rewarding in-world tasks to be performed on an in-world schedule.
For example, watering the plants every morning in Stardew Valley, or having to return to town to recover mana in an RPG. These tasks give you specific things you are strongly pressured to do (traction), but also can only be done for a short while before pushing you to go do other things (flow). Typically, these mechanics adjust over the course of the game and to the preferences of the player - some players love visiting towns and talking to people, others just want to shop and get back out on the field.
Something like a hunger meter in a survival crafting game is not a structured play mechanic, despite appearances. The goal of a hunger mechanic is to push new players into growing food and engaging with a core construction loop, but the actual task (eating) is not a mechanic with any traction or flow. It's simply a mechanic to guide the player into engaging in the first place - more of a tutorial mechanic rather than a pacing mechanic.
This becomes extremely clear as you reach mid/late game and eating just becomes an annoyance rather than an opportunity.
The tiered play mechanic, where players can accomplish a certain amount with the setup they have now, and then need to find new resources.
For example, in Minecraft you can do only so much with materials in your starting biome. You are pushed to dig deeper, search further for newer resources. This contains a number of staggered resource tiers, culminating in things like creating a portal to Hell so you can mine it.
This is a very common mechanic, and can be seen in every crafting game.
However, there are a lot of other ways to do it. For example, in an RPG, you need to move onto the next town to get new equipment, new story. In Skyrim, you'll eventually need to either leave the woods for the towns or leave the towns for the woods, because you'll run out of interesting things to do.
The idea behind all these tiered mechanics is that the player chooses when to leave. Usually, it happens just before they consciously realize they're bored of the current options. Players build their cool wooden Minecraft mansions, and when they start to run out of steam they naturally consider going abroad for new materials, or digging down to find some redstone or something.
A counterexample would be a game where you have 1000 gold to spend, and then have to go earn more. This is, again, just a tutorial mechanic rather than a pacing mechanic. A pacing mechanic would be "no matter how much gold you earn, there are things which cannot be bought with gold."
How you earn gold could also be a pacing mechanic.
Also, it's worth noting that tiered play mechanics can easily go wrong if you give any hint that there are a certain number of things to accomplish. This is common in RPGs: sidequests are intended for players that enjoy faffing about and moving slowly. But they accidentally sidetrack a lot of players that don't particularly enjoy that, but see them as tasks to do rather than optional crap for more relaxed players.
Let's go into detail.
Now that you understand the intent of a pacing mechanic, what makes a pacing mechanic good, or bad?
A good example of bad pacing mechanics would be No Man's Sky, even after their most recent update. It's clear that the mechanics are built around the same concepts as things like Minecraft. There's tiered materials, unlockable research, different biomes, etc. Why does No Man's Sky only charm a few of its players?
It's because the traction and flow system isn't properly set up. It's got the same basic mechanics, but they're not engaged properly.
Their version of traction is to require the player to keep topping up their tools and engines and stuff. However, this is a stick rather than a carrot.
It doesn't pull the player in by offering them rewards if they do it, it punishes the player by grinding the game to a halt if they don't do it. It's got more in common with a cash shop energy system than a pacing mechanic, even though there's no cash shop!
The traction system of other games? Well, watering crops results in incremental progress towards harvesting crops. Also, it doesn't require you to wander across a new hellscape in search of water - water is right there, you just have to do the grunt work. Returning to town to restore your MP? That gives you dozens of opportunities to power up your characters, get new quests, and so on. Also, you can adjust your battle strategies to minimize the need to do it.
There is a hint of what it would be like with the right traction mechanic, since building your bases requires quite a lot of specific kinds of materials. It would be an opportunity for me to build a giant wooden castle, steadily exhaust everything I can do with wood, then begin building a metal underwater base or something. In this way we would get a nice, tiered setup.
In addition, the upgrades are not properly integrated into the pacing mechanic. In order to buy upgrades you need to wander the world looking for buried treasure, which magically turn into treasure points which your machines magically turn into new blueprints. This isn't necessarily bad, but it's not a good pacing mechanic. There's not much traction or flow involved, and it interferes with my ability to explore the nature of having a wooden castle. If I dig up more treasures, I should probably spend them on unlocking more advanced base equipment in the next base tier, rather than wasting them unlocking the ability to build a window.
If the traction side is flubbed, the flow side is just as bad.
I think the theory was that the limited inventory space would keep you from wanting to stockpile specific resources, meaning that you would be pushed into moving forward. That could have been a good flow, but it doesn't work in practice because the universe doesn't really support that kind of motion. If the game environment doesn't support your pacing mechanic, then your mechanic won't work.
There's some promise to the idea of compressing resources down into denser, more high-quality variations of themselves. This could theoretically produce a nice loop where you harvest a lot of a given planetary resource, spend some time condensing it into an easy-to-carry variant, and then move on once you have a complete stack of ultra-dense stuff.
I think a game could be built around that pacing mechanic really easily... but NMS is not that game. Instead, it features a smattering of annoying, slightly rare materials that take up way too much of your limited inventory space and can't be meaningfully compressed. Trying to hunt down rare materials would be fine in a game with different pacing mechanics, but these mechanics actually make that task extremely annoying.
This isn't to say NMS is "bad". It does hit the sweet spot for a fair number of people. It's simply that the pacing mechanics aren't really doing their job.
Conversely, there are games with spectacular interlocking pacing mechanics, and those are well worth studying.
Stardew Valley is probably the current king of this. With at least half a dozen interlocking, adaptive pacing mechanics, it appeals to a surprisingly broad player base.
Daily energy is the most basic mechanic. High-intensity tasks like harvesting, chopping wood, and adventuring can only be done sparingly, which pushes the player to then do low-intensity tasks such as exploring, charming the townsfolk, cooking, and so on. The low-intensity tasks show the player how to unlock more efficient high-efficiency tasks, which makes a nice circle.
Daily hours is another basic pacing mechanic. You can only get so much done in a day, even if you short circuit the energy mechanic with expensive foods. This pushes you to do at least some high-intensity tasks, rather than just doing a bajillion low-intensity tasks, to make the most of your daily energy.
Tending the farm (watering, milking, etc) is a structured play pacing mechanic. It gives you a mostly-reliable task to do, and each time you do it you get a little bit of gain - whether in the form of direct goods or moving towards a harvest.
Crop management (planting, harvesting) is another pacing mechanic, and allows you to determine how much farm tending you want to live with while also juggling your daily energy.
Tiered tools (sprinklers, better axes) is a tiered pacing mechanic that pushes you to do things besides simply farm, because they making farming more efficient.
Processing (jams, ores, etc) is another structured play mechanic where it takes time to refine things and you're rewarded for efficiently returning on schedule to set up the next batch. But, like all these mechanics, it's largely player-driven: players can simply invest in more hardware if they want to get all their refining done without needing to tend it too much... or they can slack off and only process a few things, because there's not that much of a need to minmax it.
All of these systems interlock, and are supported by the structure of the game's world. Each time the player engages with one, they are rewarded (traction), but only to a certain extent, then they are pushed to do other things (flow). It's an interlocking matrix of pacing mechanics, where the player can invest in a number of different ways to change the dynamics.
It's just a spreadsheet, sure. But the pacing mechanics make it a damn fun spreadsheet.
Plus there are some minigames if you need a change of pace.
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Those are my thoughts on pacing mechanics.
What are yours?
