Courtesy of Hottagames Co., Ltd.

Tower of Fantasy leverages Unreal Engine to bring open world action to mobile, PC, and PlayStation

Mike Williams
Kee Zhang is a game producer from Perfect World Games’ Hotta Studio. He has been involved in developing online games for 19 years.

While working as a game producer at Black Gold Studio's Snail Games, he participated in the development of Voyage Century, the first three Taichi Panda games, Lineage 2, and so many more.

He joined Perfect World Games in 2018, forming Hotta Studio, leading his core team members in the development of Tower of Fantasy until now.
The real "fantasy" at the heart of Tower of Fantasy is the ability to explore a vast series of beautiful open world environments, enjoying action-packed combat with your online friends. Hotta Studio improves upon that fantasy by allowing players to enjoy this experience on Android, iOS, PC, PlayStation 4, and PlayStation 5.
Courtesy of Hottagames Co., Ltd.
Hotta Studio is a team built around veteran developers, but Tower of Fantasy is still the studio's debut title. The team had to not only create a fun action combat romp, they also had to ensure that it ran smoothly on all platforms. To make that happen, Hotta Studio turned to Unreal Engine, which helped them optimize the game so that every region of the planet Aida looked great, whether you were playing on your smartphone or PlayStation 5.

We spoke to Hotta Studio about developing Tower of Fantasy for online cross-platform play on mobile, PC, and PlayStation 4/5, and how Unreal Engine helped make that fantasy a reality.

Can you tell us what Tower of Fantasy is about?

Kee Zhang
, Game Producer: Tower of Fantasy is an open world game developed by Hotta Studio, available on multiple platforms and globally distributed.

Players take on the role of a Wanderer, embarking on adventures alone or with companions on the energy-devastated planet called Aida. We have created a highly immersive and free open world, allowing players to explore. The game features action combat gameplay without the constraints of specific class types, allowing players to freely switch roles. In addition to our popular characters, called Simulacra, players can customize their own unique appearance through facial customization and outfit combinations. Furthermore, players can connect with other people online, team up to defeat bosses, or simply enjoy the beautiful scenery together.

Considering Tower of Fantasy is Hotta Studio’s first game, can you explain why it was chosen as the studio’s debut release?

The name of the studio, Hotta Studio, is derived from the pronunciation of Tower of Fantasy ("幻塔"). Although the team is young, we also have industry veterans among the core members, so we still have extensive experience in development.

However, we never expected that from 2018 on, we would face obstacles in this completely unfamiliar open world genre. It forced us to overturn our previous expectations and—just like when we all first started in the industry years ago—explore new territories and overcome various challenges in order to find a way forward.
Courtesy of Hottagames Co., Ltd.
Were there any games or works that inspired the development of Tower of Fantasy?

As an open world game, our goal is to create a truly immersive world for players. We call the concept "worldly experience" and we have always pursued it. 

How do we bring a virtual world in a game to life? We believe that freedom is crucial. For example, when going from one mountaintop to another, players can choose to fly, interact with creatures on the map, use equipment, or even utilize combat skills. We don't want to restrict players; instead, we encourage them to find different solutions to the same question.
One day, while enjoying the sunset alone in the game, I suddenly thought how great it would be to have a few companions to pass the time with me here. This may be one of the reasons why we turned Tower of Fantasy into a multiplayer online open world game.

Furthermore, we also love God of War: Ragnarok. We believe their seamless map teleportation fully utilizes the high-speed SSD and Kraken hardware compression features of the PlayStation 5. As seasoned action game enthusiasts, our team has always strived for excellence in refining combat and the sense of impact. We want players to have a more exhilarating experience in combat and have room for combos, rather than simply relying on numbers to defeat bosses.

Can you explain how the game’s real-time combat system works?

In the introduction to Tower of Fantasy, the keywords "action" and "act" are always mentioned. In combat, we have incorporated many classic elements of action games, such as double jumps, mid-air combos, and time dilation after dodging, also known as "bullet time."

Implementing a feature like bullet time is relatively easy in single-player games, but it becomes much more complex in an open-world game with multiplayer capabilities. What are the boundaries of player interactions? How wide is the scope of bullet time? How long does it last? Should there be a cooldown? How long should the cooldown be? These are all things that require careful tweaking and countless iterations, which can be quite a headache. However, we really love this feature, and I believe many action game enthusiasts do too, so we persisted and made it happen.

And then there's the mysterious "sense of impact." Achieving a satisfying sense of impact requires perfect coordination between visuals and button feedback. For example, how the sword gleams when a player swings it, creating the feeling of every strike hitting flesh. It takes a lot of time to get it right. Here, I want to apologize to the amazing artists, as I often dragged them into lengthy discussions just for a specific particle effect.

We also made efforts to diversify the combat mechanics. Players can use grappling hooks to approach enemies, climb on the backs of bosses for attacks, or even perform environmental kills by knocking enemies off high edges or utilizing objects in the surroundings. In short, there are various ways to engage in combat. In this open world game, we hope players can experience deep and engaging battles. That's a small dream from an old action game player like myself.
Courtesy of Hottagames Co., Ltd.
Can you talk about why you incorporated a character creator in Tower of Fantasy?

In the world of Tower of Fantasy, we aim to collaborate with players in creating characters. We take charge of designing the Simulacra, including various NPCs, to enrich the world. Meanwhile, players can freely create their desired virtual appearance using the character customization system and embark on an adventurous journey in this world.

As a multiplayer online open world game, when we provide players with the space for autonomous creation, this world becomes more than just the joys and sorrows of created NPCs. The bonds formed between players become the catalyst that brings the entire world to life.

Therefore, we not only listen to the voices of players but also hope to provide them with more creative space in Tower of Fantasy in the future!

Outside of the player character, Tower of Fantasy has a wide and varied cast of characters called Simulacra. Can you elaborate on how the team designs the game’s distinctive Simulacra?

When creating Simulacra, we prioritize aligning them with a specific worldview and character trait, while also considering the visual effects after modeling. In the initial stages, we engage in repeated discussions and gradually establish a general direction, producing various design drafts.

For example, when designing the traditional Chinese-style character Liu Huo in Domain 9, we combine the cheongsam and the bun hairstyle with vibrant primary colors to allow players to feel the immense energy within this young girl, while also incorporating tech elements to remind players that this is still a world within the realm of science fiction.

Additionally, we aim for the characters in the game to be realistic and lively. Therefore, when designing characters, we strive to ensure that each equipment accessory has reasonable functionality. While maintaining a fashionable style that can be realistically worn.

The effort behind Simulacra creation listed above is just the tip of the iceberg, but the fundamental principle remains unchanged: to align with the worldview and express the aesthetic we desire.
Courtesy of Hottagames Co., Ltd.
Tower of Fantasy has vast, visually-impressive, open world maps for players to explore. How does the team design the maps to be visually unique while also offering extensive chances for player exploration?

As mentioned earlier, as an open world game, we aim to create an immersive and dynamic virtual world in Tower of Fantasy.

For example, when designing the maps, we have given multiple natural stats to the interactive items in the world. We have also designed rich interactive logic for these stats and placed them in the expansive game space, allowing for random encounters and generating diverse and interactive chain reactions. We construct the world from both a lower and higher level perspective, striving for ecological coherence. Map designs like these enrich the overall world ecosystem while providing players with more choices during their exploration and decryption processes.

Relics are items that help players in combat and exploration, like the high-flying Jetpack or the Quantum Cloak, which gives players limited invisibility. How does the team approach creating these special items that offer new ways to fight and traverse the world?

Our philosophy is to provide more problem-solving approaches without affecting the outcome of battles and exploration. For example, by combining certain weapon skills with the open world, players may discover a marvelous answer which we call a "traveling weapon."

Moreover, during the development process, we want the act of leaping and slashing during combat to be different from normal attacks. Climbing to the top of a mountain and gliding onto a boss using a jetpack will have a different effect than using a fire-burning effect. The Omnium weapons used in combat, such as grappling hooks, have special abilities. Different players with different weapons will have different solutions when facing the same mechanism.

When it comes to exploration, we don't provide too many hints for puzzle-solving, but allow players to discover and utilize them on their own. We don't explicitly disclose the available types, instead, we leave the decision to the players. Through weapon combinations, players can even uncover hidden types of characters.
Courtesy of Hottagames Co., Ltd.
As a live service game, Tower of Fantasy is continuously in development. Can you talk about the opportunities of ongoing development for each update?

In Tower of Fantasy, we've always emphasized that the open world is not a lonely place. Here, players can join forces and socialize with other players through online co-op. Whether you're near a shelter, in the wilderness, or by the harbor, you'll encounter others who are exploring this world just like you.

"We're in the same world" is the feeling that Tower of Fantasy aims to provide players, and it's a way to create a sense of immersion in the world. How to construct and enhance this immersion is an important topic that we continuously explore with each update.

Tower of Fantasy is available on iOS, Android, PC, Playstation 4, and PlayStation 5. How does having all of these platforms change how you approach the game’s ongoing development?

After achieving a multi-platform release, we are committed to optimizing and ensuring consistency in the effects across multiple platforms. This is an ongoing optimization process, and we are genuinely delighted to see Tower of Fantasy being embraced by users on various platforms, which gives our developers even more motivation.
Courtesy of Hottagames Co., Ltd.
Can you provide your thoughts on using Unreal Engine to develop a cross-platform game across mobile and PC?

From the very beginning of our design process, we aimed to achieve consistent performance for Tower of Fantasy across multiple platforms. The excellent support for cross-platform development made Unreal Engine our top choice. Through multi-platform development and optimization based on Unreal Engine, we hope to make Tower of Fantasy a benchmark product for cross-platform gaming in China.

Why was Unreal Engine the right choice for Tower of Fantasy?

As an open world game, the visual presentation is a key focus in Tower of Fantasy. We utilize Unreal Engine 4.26, and through extensive optimization and improvements during our four testing phases, we have achieved a level of visual performance that is both stunning and impactful in the vast world of the game. Additionally, the support for open-source code using Unreal Engine allows us to customize and modify certain effects and functionalities according to our needs.

As mentioned earlier, from the early stages of Tower of Fantasy's development, we planned to achieve consistent effects and performance across multiple platforms, and Unreal Engine was the perfect choice for this.

Lastly, the highly flexible Blueprint system in Unreal Engine greatly enhances the efficiency of our team's game design process, allowing for the creation of gameplay models with a high degree of freedom.
Courtesy of Hottagames Co., Ltd.
Were there any other Unreal Engine tools that were particularly helpful during the game’s development?

The powerful Material Editor has given us higher development efficiency and more exquisite visual expressions in the artistic effects. For example, while developing the popular map Mirroria, it really played a significant role in achieving the visual presentation of the collision between cyberpunk and a traditional Chinese style.

Do you have any tips you can share to game developers using Unreal Engine for mobile development?

Unreal Engine has good support for mobile devices, and during development, one needs to pay attention to the number of polygons, draw calls, and whether the memory is within a reasonable range to ensure smooth gameplay. Additionally, we recommend optimizing art assets specifically for mobile platforms. The engine is incredibly powerful and provides developers with ample room for creativity.

Thank you for your time, where can people learn more about Tower of Fantasy?

Kee: You can follow us on Discord, Twitter, and YouTube. Just search for "Tower of Fantasy" and you'll be able to find us. You can also visit our official webpage.

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