Warframe

Staying relevant as an old game

Warframe is an 11 years old looter shooter game. Despite its age, it stays highly relevant, with a playerbase that has only grown in all those years. This was only possible due to a satisfying gameplay loop, combined with regularly added content.

Weapon modifications

One of the core systems I believe to have aided in creating such a cult following in this game is the weapon modification system. The system uses cards, that can be slotted into weapons to give them a power boost. Each card has different effects, and different weapons prefer different cards.

Winning the fight before it starts

The reason this system is so relevant is that it determines the player's fighting strength before they even enter a mission. Good weapon modders will be significantly more powerful than bad modders, though the skill floor is low enough that average players can get through the missions just fine.

How warframe does it

What makes warframe's system special is that there's no one way to modify a weapon. By combining critical hits, and status effects, which every weapon can make use of, but some better than others, you give the player a choice in what to focus when modifying their weapon. To take it a step further, each damage type can be used either for their damage multiplier against certain types of enemies, or for their status effect, which applies some kind of debuff to the enemy, a system so complex that the wiki for damage types has over 10.000 words.

Layering upsides and downsides

To create even more depth, warframe uses what they call "corrupted mods". These mods can give an even bigger power boost in one stat, at the cost of lowering another stat. So now the players need to choose how much of a boost they want, and wether the negative stat is worth it or not. This multi-layer depth allows player expression to flourish. Every player will pick different weapons through their modding preferences, and create unique playstyles that cannot be replicated in any other way.

Replicating this in one's own game

To replicate this design principle, of creating depth in item modification/personalisation system, to one's own game, it is important to create meaningful choices. While having one slightly superior option is pretty much unavoidable (otherwise known as a meta), having different superior options for different reasons creates tradeoffs. Adding layers of these tradeoffs is what creates the depth of this system. It is paramount that the player cannot choose all options, for this system to work.

Other notable games that do this well

This is an non-exhaustive list of games that I have played that implement similar depth in their item modification systems, and their respective systems:

Mechwarrior's paperdolls

Mechwarrior Online
Mechwarrior 5 Mercenaries
Mechwarrior 5 Clans

Crossout's build system

Crossout

Robocraft's build system

Robocraft

Destiny's weapon and armor mods

Destiny 2

Steel Division's division editor

Steel Division 2
WARNO