A Strategic Approach to Level Design: Campaign Breakdown of Immortal Pillars

 Modern RTS Campaign Design

"Age of Mythology: Retold" is the remastered version of the classic RTS game Age of Mythology. Our team contributed to the creation of both the civilization and campaign levels in the Immortal Pillars DLC. In the previous article, I shared the creative process behind the Chinese civilization. This time, I’ll focus on introducing a strategic approach that helped us craft campaign levels that demand careful thinking and deliberate decision-making at every step.

In traditional RTS games, campaigns are often seen as secondary to skirmish modes, mainly serving to introduce the unique features of each civilization. But by today’s standards, tutorial-focused missions are no longer enough to captivate players. A compelling campaign must combine enjoyment, challenges, and strategic depth. It must also integrate tightly with narrative pacing and story events, delivering a cohesive experience that balances tactical gameplay with storytelling.

This was not an easy task, but it offered us a deeper appreciation for the true potential of strategic design.

Image source: Age of Mythology: Retold — Official Immortal Pillars Teaser Trailer | TGS 2024

Start with the Ultimate Goal in Mind, and Advance Step by Step

Each campaign mission is built around a clear primary objective, but we didn’t want players to simply achieve victory by overwhelming brute force. Instead, the path to success is broken down into a series of interlocking challenges. Completing each challenge rewards the player with valuable resources, new units, or divine powers, all of which bring them closer to the final victory condition.

This structure adds rhythm and a strong sense of progression to the experience. By creating a positive gameplay loop: challenge → reward → advancement—players are consistently motivated to push forward. This is the essence of strategy-oriented design, much like gaining experience and leveling up in an RPG. The more challenges players overcome, the more advantages they accumulate. Eventually, building the strength needed to conquer the mission’s ultimate goal.

Overcome Challenges and Progress Step by Step

The Iron Triangle of Challenge Design: Problem, Reward, and Story

When designing challenges, we consider three key elements: problem, reward, and story. These three components form a solid triangle that achieves a holistic experience.

Challenge Triangle: Problem, Reward, and Story

Problem: What Does the Player Need to Solve?

The problem tests the player’s use of specific abilities or resources.

For example, if we want the challenge to emphasize the use of hero units, the problem might be a stronghold that is occupied by myth units. It requires the player to train or send heroes to resolve the situation.

Problems and their solutions originate from the game’s “rock-paper-scissors” relationships. Different combinations of unit types can create basic problems, while considering factors like terrain and unit formations leads to more advanced and varied problem scenarios.

Key questions to consider when designing problems:

• What combinations of unit types are involved?

• How does the arrangement of units affect the situation?

• What are the terrain’s height, width, and spatial constraints? Are there any obstacles to consider?

• What solutions does the player have? Which units or god powers provide the answer?

Reward: What Does Success Yield?

Rewards should relate to the overall strategy, providing players with tangible progression incentives. For example, in a map requiring a naval assault, capturing a fishing village might grant the player five transport ships, enabling the army to land on the enemy’s island.

Key questions when designing rewards include:

• What does the player gain?

• How does this reward impact strategy or open new possibilities?

It’s important to note that rewards don’t have to be a tangible resource or ability; they can also trigger events or missions that further expand the player’s experience and adventure.

Story: How to Seamlessly Integrate Problems and Rewards?

The experience feels artificial when problems and rewards are simply placed side by side. This is where the story plays a key role, naturally connecting the two and enhancing the overall immersion of the Challenge.

Key questions to consider when crafting the story:

• What is the environment where the challenge takes place?

• What happened before this moment?

• What is the current situation?

• What developments will follow after the challenge is resolved?

An example from the beginning of Scenario 2 of Immortal Pillars illustrates the integration of problem, reward, and story design:

The player encounters an enemy squad raiding a village (environment). The hero leads the troops to intervene (problem). If the player effectively uses archers, they can quickly eliminate enemy infantry while minimizing losses (solution). Once the enemy is driven off, the player gains control of the village (reward), which can now produce new units to strengthen the army (strategic advancement). The troops then report that many villagers have scattered to avoid the fighting (past event), prompting the player to set out and find them (reward: new development)…

The Opening Challenge of Scenario 2 in Immortal Pillars

Challenge Template

In the campaign missions of Immortal Pillars, we crafted a rich and diverse experience through various types of challenge events. Below are some common challenge templates used in campaign design:

1. Branching Challenges

This type of challenge centers on a shared objective but offers different paths. Players typically face two or more attack routes, each presenting distinct tactical challenges and resource allocations.

This template provides multiple strategies for players to choose from, encouraging strategic decision-making.

For example, in the map below, which requires a naval assault, there are two suitable attack directions at the target location. The southern route features open terrain but is surrounded by walls and several archer towers. The eastern route has fewer defensive structures but hosts several warships.

Players must choose a strategy to capture the position: attacking from the south requires building siege weapons and transport ships, while attacking from the east demands a stronger naval force.

The varied setups in the south and east steer players toward different strategic decisions.

The branching challenges also echo the Minor God selection mechanic in Age of Mythology. Within branching challenges, two distinct paths correspond to different strategies, guiding players to leverage the unique traits of their chosen Minor God when planning their approach.

For example, in Scenario 3 of Immortal Pillars, there are two routes: the eastern path features a higher concentration of defensive units, while the western path has fewer defenders but is protected by thick city walls (see the image below).

The western (left) and eastern (right) routes present different problem setups.

Choosing the Minor God Xuan Nü grants the myth unit Qilin, which can heal nearby units, enhancing their survivability, making it ideal for the eastern route.
In contrast, choosing the Minor God Hou Tu summons Qiong Qi, a beast capable of switching to the flying stance. It can soar over the western route’s walls and launch attacks from behind.

2. Multi-Sub-Objectives

This type of challenge presents players with a series of repeated objectives that, once completed, contribute to strategic progress. Although the tasks may be similar, varying specific elements and rewards help maintain a sense of freshness throughout gameplay.

This template sets a goal that demands greater player commitment. Upon completion, it delivers a satisfying sense of accomplishment, like achieving a major feat.

In Immortal Pillars Scenario 5, we employed this design. In that scenario, three massive ballistae are attacking the Celestial Pillar, and players must eliminate each one. To increase variety and difficulty, we introduced different enemy types and tactical setups for each target:

• First Ballista: Guarded only by infantry.

• Second Ballista: Features both infantry and archers, with a more tactical formation.

• Third Ballista: Defended by a full human regiment and several myth units, significantly raising the challenge.

To maintain the pacing and momentum, after each ballista is destroyed, a divine beast Qinglong joins the player's forces, giving players a tangible power boost and encouraging continued progress.

Ballista Threat in Scenario 5 of Immortal Pillars

3. Defensive Challenge

In this type of challenge, enemy forces relentlessly launch attacks against the player. The player must strategically position their units, upgrade technologies, and construct defensive structures to withstand the continuous waves of enemies.

This template is ideal for testing the player's ability to manage defenses and allocate resources effectively, making it well-suited for creating a high-pressure experience.

If the goal is to make the player feel overwhelmed, this is the optimal choice. In Immortal Pillars Scenario 8, players must defend their base as enemy forces attack from three directions. Players must strengthen fortifications and deploy troops to repel the invaders.

4. Time-Limited Challenge

This type of challenge introduces a strict time limit within which the player must conquer a specific location or achieve a particular goal—failure to do so results in mission failure or severe penalties.

This template also creates a sense of urgency and difficulty, but unlike defensive challenges, it places more emphasis on offensive execution and strategic decision-making.

In Immortal Pillars Scenario 6, the player must reach the destination before the Celestial Pillar is destroyed by lightning strikes. As the enemy continuously strikes the pillar with lightning, the player must carefully plan the most efficient route and determine the best approach to reach the goal in time.

Using POI to Adjust Level Pacing

In addition to challenges, the insertion of Points of Interest (POIs) can effectively adjust the pacing of a level, creating a rhythm that balances tension and release throughout gameplay.

The design of POIs is widely used in open-world games. These locations often feature striking and visually appealing landmarks that serve as anchors to attract players toward them during exploration.

I define POIs as lightweight event areas designed to enrich the exploration experience. They typically feature distinctive terrain or art assets that attract the player's attention. Unlike challenge points, they do not demand intensive gameplay or tactical planning. Visiting a POI may trigger a short dialogue or reward the player with a minor item.

POIs serve to modulate gameplay pacing by interspersing moments of relaxation and curiosity between intense challenges. They foster a positive exploration-reward loop and introduce delightful surprises that break expectations.

POIs appear in many campaign levels. One example is the ruined Celestial Pillar in Scenario 3 of Immortal Pillars, which acts as a POI. Its grand but broken form piques the player's curiosity, visiting it triggers a narrative dialogue and grants a relic reward.

POI: The Ruined Celestial Pillar

Conclusion: Linear V.S Non-Linear Level Design

In level design, there are generally two types: linear and non-linear. Linear levels usually have a clear final objective and guide players through a series of events in a fixed order, leading them step by step toward the conclusion. In contrast, non-linear levels hand the choice back to the player, allowing them to decide how and in what order to tackle challenges.

The advantage of linear levels lies in the designer’s tight control over the player experience, which is especially beneficial for structured tutorials and narrative pacing. On the other hand, non-linear levels emphasize player freedom and strategic variety, significantly enhancing replayability and overall enjoyment.

Both types of levels are present in Immortal Pillars, but given the nature of strategy games, Non-Linear Design offers players a richer strategic depth.

To implement non-linear level design, we disperse multiple challenges across the map, allowing players to freely explore and conquer them one by one. The overall structure can be imagined as a scaled-down open world. The main objective represents the primary mission line, while these challenges function as side quests surrounding it. None of these side quests stand alone; by conquering them, players grow stronger and eventually gain the strength to overcome the main mission.

Epilogue

The contents above summarize the design insights I gained throughout this development process. For me, this project has been a pivotal milestone in my career, marking the first time I deeply considered the composition and layout of campaign levels from a holistic perspective. Each level no longer felt like an isolated challenge but rather a tightly connected, interactive mini-world. It’s exciting when player choices can influence the course of that world—such interactive design is truly rewarding.

In fact, I have much more to share about campaign design, especially Scenario 7, which stands out as the most unique level in the entire AOM campaign. Watching numerous KOL livestreams, I have heard many moments of awe and high emotions from this level. Their reactions inspired me. I decided to start a new topic: What kind of magic creates such a powerful experiential turning point? I believe this topic deserves a deep dive and a dedicated article of its own.