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Adding depth and replayability using gameplay modifiers

For the past few days I've been working on a feature called "Modifiers" in my roguelite strategy game Citadelic. It's going to be one of the elements of the so-called "meta-progression" in the full version of the game.

The term "meta-progression" is sometimes used to describe a game mechanic, which lets the player unlock new content that typically only becomes available the next time they play. In some games these are permanent upgrades that give the player some kind of advantage - stronger attacks, more health, etc. Unlocking these upgrades makes the next attempt easier, allowing the player to progress a little bit further.

I'm not a fan of these kinds of permanent upgrades, actually. Citadelic is primarily a strategy game, so I want to avoid adding elements that would give a player an advantage for simply spending more time in the game. This would feel cheap, ruin the game's balance and incentivize players to "grind" for new upgrades instead of thinking strategically.

Another type of meta-progression is the kind that opens up new gameplay possibilities, without necessarily making it any easier. Team Fortress 2 is an example of this: the player can unlock new types of weapons that, in order to be used efficiently, require different play styles. This means that no weapon is really "better" than any other of its type - they are essentially just different ways to play the game. I've taken a similar approach - all of the meta-progression in Citadelic is there to give the player more options and add variety to the game, while keeping it challenging.

But why keep these options locked away? Why not give the player full access to all of the game's features from the start?

Let me give you a quick summary of the gameplay loop in Citadelic first.

Citadelic gameplay
Citadelic gameplay

The game, like many roguelites, is played in short sessions (or "runs"). The player builds a base and defends it from waves of enemies that evolve randomly each time, developing different strengths and weaknesses. This randomness forces the player to adapt and keep making decisions, such as what types of resources to focus on getting, what types of defenses to develop, which upgrades to invest in, and which reward to pick at the end of the wave.

The game starts out simple, but gradually becomes more complex as the enemies grow stronger and strategy becomes more important. As the player learns the game and survives more waves, new advanced difficulty modes get unlocked. Harder difficulty modes alter the enemy evolution algorithm, giving the player less room for error.

So there is already plenty of depth and replayability here, and adding any more complexity could easily overwhelm a player that hasn't learned the basics of the game yet. Being overloaded with too much information isn't fun, no matter how good the game might become once you learn how it works.

Meta-progression can be used as a way to gradually add new mechanics to a game without confusing new players. In Citadelic, the player is rewarded with experience points based on their score at the end of each game. These experience points can then be spent to permanently unlock some things (the player chooses what to unlock). In this post I'll focus on one type of unlockable elements - gameplay modifiers.

Selecting modifiers in Citadelic
Selecting modifiers in Citadelic

A gameplay modifier is basically a way to change the game rules, enabling new kinds of strategies that weren't effective before. Each modifier, when enabled, always gives the player one advantage and one disadvantage. The player can enable multiple modifiers at the same time, which can result in interesting combinations that completely change the gameplay.

For example, one of the unlockable modifiers is called Industrialism. Its description reads: "Ore income from production is doubled, but there is no ore income from kills."

Ore is one of the crucial resources in Citadelic, and killing enemies is one of the main ways to get more ore. Players can also build ore mines to get a passive income of ore at the end of each wave. The usual approach is to rely on both ore mines and killing enemies for a steady income. Enabling the Industrialism modifier changes the dynamics: the player now has to focus on building ore mines and enhancing their production using upgrades, augments and supplementary buildings (refineries, which improve the ore production of nearby structures). This approach can potentially yield a much bigger income, but carries more risks, because the production buildings take up valuable space, and a bigger base is harder to defend.

Defending a base full of production buildings in Citadelic
Defending a base full of production buildings in Citadelic

Another unlockable modifier is called Durability: "All buildings get 1 extra hit point, but the cost of repairing buildings is doubled." Enabling this modifier discourages making repairs too often, forcing the players to only repair their most valued buildings. The increased hit points may be more advantageous, for example, if the player decides to build a larger number of low-level structures that would be cheaper to rebuild than repair when damaged.

The player may choose to enable both Industrialism and Durability at the same time, and then try to combine the advantages of both modifiers to come up with new strategies that weren't viable before. Maybe they'll try building nothing but ore mines around their base, building a sort of a barricade against ground units. Of course, whether that's an effective battle plan is a different question, but experimentation is always a big part of the fun in strategy games.

Currently there are 8 different modifiers in Citadelic, which can be used on their own or in combinations with each other. This already adds a lot of depth to the game, so I'm not planning on adding any more at the moment. That may change in the future, though.

Another element of meta-progression in the game is the ability to customize the player's main base. I will cover that bit in my next article.

If this is your first time hearing about Citadelic, check out the free demo on Steam and let me know what you think. Add the game to your Wishlist if you liked it!

Next Article

Base customization for different play styles in Citadelic


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