Why are some games modded more than others? Thread

I am not sure if this belongs here, in Development Banter, in Ideas and Concepts or maybe even some where totally different... But I will just post it here and let the axe fall where it may and I apologize. *swallows hard*

I notice there are certain games such as Half Life 1 & 2 that have an extraordinary way of having people mod for them. While other games, even if they are beloved by the community, not so much. Why is that?

Is it that certain games are more easily modded? Some game developers encourage modding of their games, more so than others? The fans of certain games just have more expertise to mod, than other fans from other games?

Take for instance Shenmue 1 & 2. Presumably not much, if at all, could be done for the consoles. But with the release of it on Steam, most mods for it are strictly texture based or sound fixes, not even NPC replacements, just better looking textures. I understand it is fairly new, but nothing that I can find are actual changes or additions to the games or even in the works to be done. No new areas, no new quests, no new fighting moves, no new game mechanics like the ability to buy from the shops (the shops and the store owners are already there), no improvement on making the kitten an actual pet simulator, no newer capsule toys or newer arcade games, etc.

The arcade games I could see being touchy on copy right, unless you use third party games with permissions or made your own clones, but the rest I would assume would be ok. But there is hardly anything. And although I am asking more regarding Shenmue, I am curious why there could be a whole slew of other games out there that have the same fate. Any thoughts? Thank you.

Depends on the tools available to make modifications to the game / make add ons. Valve have released pretty good mod tools for the community to use whereas I wouldn't even know how you would start modding Shenmue. There was a bunch of people recreating it though!

When it comes to modding games, you could probably put most mods into one of three categories:

1. Surface-level - these mods modify textures, change sounds, or make changes that affect visuals but don't generally alter the experience in a significant way.

2. Overhauls - these mods generally modify quite a lot of a base game but don't features lot of straight up "new" content; rather, they modify the existing game with maybe the occasional new mission, gameplay refinements, and possibly the same changes as in case 1.

3. Total Conversions - these mods can change a game fundamentally into a completely different experience. Maybe a new storyline, or a separate theme altogether (i.e. a Star Wars total conversion for, say, New Vegas).

If you want to do 2 or 3, you generally need tools, or the game needs to be unobfuscated/decrypted enough by third party developers to achieve this level of changes. Surface level texture injection is relatively doable in most games provided you're handy with a hex editor and know how to recognise certain header data for textures, and tools to allow for surface level modifications are naturally the easiest to make.

The games that are easier to mod and have more options are, on the whole, more commonly modded, for obvious reasons. I've made two mods that were the first significant mods of their kind for their respective games, but both were an absolute chore to make, and one of them I would say barely fits category 2 since the gameplay changes it makes aren't very significant.

That being said, there is value in mods from category 1. Changing visuals in a game can still result in different memories about an experience, leading to a fresher experience overall. It's just about how easy it is to do even that. If there's no documentation, no tools, and no official support, the end result is all the R&D has to be done by enthusiasts before modding the game can go any further. When it takes hours of trial and error to change one texture of an asset, that makes looking into any other significant changes daunting.

tl;dr the easier a game is to mod, the more mods there are for it.