14 April 2023

What's the defining feature of an MMO game in general?

What's the defining feature of an MMO game in general?

I'm an old-time MMORPG fan and actually switched my career to gamedev specifically to gain experience and, maybe, one day, start my own MMO project (yeah, I know).

I was thinking a lot about pros and cons of the genre, about its evolution over the years and noticeable player base degradation (or, rather, lessening hype). During time, I asked myself the question from the title - how we can define the MMO genre in general? What is the core difference between MMO games and non-MMO games?

was originally posted on reddit

Definition of MMO genre

yet another one...

My answer is - an MMO game is a social network by its nature, implemented via game mechanics. Of course, not as a facebook or other "web" social networks, rather it’s about establishing connections and relationships between people (players).

With that definition in mind, any game mechanics that encourage player-to-player interactions of any kind are good for the game (making it more MMOish), and mechanics that prevent or discourage such interactions are bad (less MMOish).

Common mistakes in MMOs game design

I believe most of the issues are going from seemingly minor features that are even considered QoL improvements for each individual game.

  1. Instanced dungeons spreading.
  2. UI options for “looking for group”
  3. NPC trade houses (“auctions”)
  4. Implementing dynamic “server channels”

So you should already see from the definition above why these points are critical for MMO games - they are limiting or preventing players from interactions between each other.

  • Instanced dungeons are a whole issue by itself, I will explain it a bit later.
  • "Looking for group" interfaces: from the first glance, it looks like a pure QoL improvement allowing players to play with other players and it looks like it encourages p2p interactions. But in fact, it makes the whole “group” thing meaningless, turning other players to “bots” from session games with matchmaking, you don’t care about them, play once and forget in most cases.
  • Similar with Auction Houses - instead of negotiating with other players, sellers and buyers just use the game UI as in single-player games. Remember the times of market squares in old chronicles of Lineage2? Not a perfect example, but it was a part of actual gameplay and p2p interactions. Between buyers and sellers, between rival shopkeepers, etc.
  • “Channels” or "phasing" - when players are on the same server, but don’t see each other for performance reasons. That should be clear, it’s just limiting players from interactions and even with high concurrent players amount, they always see a half-empty world with a couple of other players suddenly jumping in time to time.

So, for myself, I coined some very core principles of which a game can be called a "true MMO" game - and, to be honest, no one from existing or existed games did not really match it completely, though some of them were/are pretty close.

Principles of a "true MMO" game

Open seamless world

no visible "loading screens" during gameplay

It’s kind of clear about “open”: players want to explore the world, etc. But the important part here is to have a seamless world in terms of gameplay. And from definition we can see why - any “loading screen” is messing with player interactions. Different loading times for different players in a group, possible ambush or chase scenarios and so on - it’s just breaking MMO gameplay.

  • Bad example: Albion Online. The world separated to zones with loading screen between them
  • Good example: Black Desert. the world is seamless, player can travel wherever they want with no loading screen

Persistent world

Every possible change done by players should remain in the world and be accessible to other players, in the limits of the game's mechanics.

This is vague, but the main reason is to give players a feeling of their impact on the world. It’s the main difference from session-based games, where the world is not saved between sessions, so progress is only possible for the characters, but not the world. And it also relates to the MMO definition as a social network - changes that players are able to make in the world are also a way to interact between players.

  • Bad example: Diablo 4. Each run players see a new level instance.
  • Good Example: Elite Dangerous. The whole galaxy is evolving with the players, exploring systems and planets, global events with consequences.

Single world

there is strictly a single instance of the world both in general and in parts. meaning no "servers", "instances", "instanced dungeons", "channels", etc

That’s simple: any technical separations are just separate players from each other, limiting or preventing their possible interactions. It can be somehow justified for multiple separate servers - basically will be just multiple instances of the MMO game, but the instanced dungeons are pure evil in the context of MMO.

Instanced dungeons are just preventing players from having an MMO gameplay and turning the game to a single-player or session-multiplayer game inside such dungeons, preventing other players to engage or interact.

  • Bad example: WoW. Father of instanced dungeons trope. Entering a dungeon, the group can't be interacted by anyone from outside, turning the game from an MMO into a small-scale multiplayer or even a single-player game.
  • Good example: Lineage 2 (circa "Chronicles 3"). Each dungeon is a part of the seamless open world. Players can be chased or engaged by another group. Fights for the valuable resources. Encouraged player-driven politics, etc.


If you think about any of those principles, you can find that each of them was mostly developed because of technical limitations game developers had in the past. Right now, it’s completely doable (yet still very complicated) to overcome those and develop a true MMO game.

Though there are more issues, of course, than just the technical complexity...

I can probably name just one title that is the closest one to the principles above - it's Eve Online.

It has an open-world - it does have a "loading" screen, but it's a part of the in-game mechanics (jump gates), so it does not interrupt the gameplay, mostly.

It has "instanced dungeons" (mission spaces, anomalies), but they are not closed from other players - they can scan and reach you even there.

It does have "auction house", market, etc, but considering the whole player-driven economy of the game it's playing mostly a positive role in contrast to "classic" MMOs. Also players have to physically carry the valuables across systems to reach the most profitable markets.

With that in mind, you can ask - why do you call something the core principle, and then pointing to an example of a game that breaks each of them?

Despite the principles being based on technical limitations, I'm mostly talking about game design here and how it's affecting the actual gameplay. So if technically a game breaks the principles, but it's not affecting the gameplay - it's fine.

Don't know a fantasy-themed MMO even remotely close to it, unfortunately.