Image courtesy of SNK

Why SNK shifted to Unreal Engine for its latest fighting games

Brian Crecente

Headquartered in Osaka, Japan, SNK develop, publish, and distribute interactive entertainment software on a global scale. Known for such franchises as The King of Fighters, Metal Slug, and Samurai Shodown, SNK continues to focus on their rich console game and arcade history.
The King of Fighters franchise has been around since the first release brought a mash-up of Fatal Fury and Art of Fighting characters to the fighting game scene in 1994.

While the original title was almost more fluke than series launch, the franchise went on to spawn annual titles until 2004, when releases slowed down to a trickle. More recently, The King of Fighters XIV hit in 2016, bringing with it a shift to full 3D graphics.

It turns out that developers SNK Studio also experimented behind the scenes with the use of Unreal Engine on that title. Then in 2019, SNK decided to develop Samurai Shodown with Unreal Engine.

The King of Fighters XV is the first in that franchise to use the engine, something we talked to the developers about in a recent interview. We also chatted with them about how the game has evolved over the years, what the future holds for Unreal Engine and SNK games, and how the team goes about building out its massive roster of characters.

The King of Fighters XIV was the first in the series to shift from the game’s classic 2D sprites to 3D graphics and animation. With The King of Fighters XV, you’ve moved over to Unreal Engine. What have those transitions been like for the team working on the title?

Yasuyuki Oda, Producer: We've been using Unreal Engine since Samurai Shodown (2019) was developed on it. The reasons we switched were that it's easier to port games made in UE and for the huge boost in graphical shaders. We were actually testing with UE during the final stages of KOF XIV (2017) development, so the transition to actually using it has been relatively stress-free.

What elements of Unreal Engine helped with that transition and improved on the game as a whole?

Masanori Tsujii, Lead Engineer: Since UE's code is so easy to customize, it allowed us to incorporate our in-house tools, which really helped us out a lot. We were able to make use of all the know-how we gained in the past, which let us focus on things like improving the user experience, thus bringing our games to another level of enjoyment.

How do you think the game’s art style looks and moves in Unreal Engine? Were there visual effects or new aesthetics you were able to achieve in this latest King of Fighters using the engine?

James Bulmer, Programmer: Using UE4, we were able to utilize the realistic lighting and shadows but also able to keep the non-realistic/stylized art style that we were after. There were also some "non-realistic" lighting/shadow requirements, for example, characters casting shadows on the ground but not on each other, but the ability to modify the engine lighting code made this possible. The ease at which materials can be edited and tweaked in real time helped us to fine-tune the look of the characters and the backgrounds, and the artists were able to see immediate results to parameter changes and such, which wasn't possible in our previous engine. We were also able to take advantage of Unreal's post-processes, in particular Depth of Field, using the cinematic-camera functionality during the cutscenes and the special moves, which added more drama and impact to the animations.
Image courtesy of SNK
What other changes did you adopt for King of Fighters XV to address some of the things players didn’t like in King of Fighters XIV?

Kaito Soranaka, Lead Game Designer: In KOF XIV, a lot of players relied on using MAX Mode Quick (during combos) because the return on investment (meter usage) was really good, but this led to a lot of matches feeling monotonous. So, in KOF XV, we thought of ways we could allow fights to develop without relying too much on Max Mode Quick.

I’ve read that when it comes to new character design, SNK starts with the storyline first. How do you take a compelling storyline and turn it into a fully fleshed-out character with both a unique look and moves that help to differentiate it from the franchise’s deep roster?

Soranaka: It's case-by-case. Sometimes you add a character because the storyline requires one, other times, you create a character and find a way to add them to the story. Typically things like how they affect the story due to their position or background and their special moves get decided near the end. For Isla, we wanted a character that would be a rival to Shun'ei, and so we built her up around having that as a base. Who Dolores is as a character was decided by her position in the story alongside being a balance to Isla. Isla is a hot-blooded young spirit, so we decided to make Dolores a calm and mysterious person.

How did you decide which characters—new and old—to include in this game?

Soranaka: Well, there was an unfolding revelation that some of the characters that were previously difficult to bring back would be resurrected during the climax of KOF XIV. So, in KOF XV, our focus was to make good on this and bring back a lot of characters that people wanted to see. Along with resurrected characters came others that were deeply tied to them story-wise, so they also had to be brought back. Of course, this does not mean that the characters not brought back were ones that weren't requested, but that we wanted to bring out a lot of different kinds of characters.
Image courtesy of SNK
One of the many ways that King of Fighters differentiates itself from other fighting games is its use of a three-fighter team system. How is that being implemented in King of Fighters XV?

Soranaka: It's not that KOF XV has a unique system or anything, but it carries on the KOF tradition of having a Battery-Middle-Anchor team setup, with the max number of power gauges increasing with each downed character. There's some fun strategy when it comes to building a team because characters that gain meter are better suited as a "Battery" (so they get played first), and characters that can dish out heavy damage thanks to an excess of power gauges are better played as a last resort (the final character, or "Anchor"). But there are some players out there who are worried that if they don't get good at using three characters, then they won't have fun, and so to alleviate their fears, we improved upon the 'rush' combo system, which allows players to pull off combos by tapping the attack button. Additionally, we universalized the command input for each character's strongest special move, and so it should be a lot easier to play with characters that you're not used to.

SNK announced it would be implementing rollback-based netcode for the game as opposed to input delay netcode or a combination of the two. What drove that decision?

Soranaka: Due to COVID-19 and its effect on the world at large, offline events have been increasingly difficult to get off the ground. So, there was a necessity to improve online functions to better facilitate online events. One way of doing this was by implementing rollback netcode.
Image courtesy of SNK
It sounds like the team learned a lot from the November open beta test for the game. What sort of changes are being implemented that were driven by those lessons?

Soranaka: We're honestly so thankful for all the feedback. From big issues like problems with the netcode to smaller annoyances like the default cursor position when choosing a character, all the feedback has been essential on highlighting what needed to be fixed, and we're hard at work doing just that.

What can you tell us about your plans for new content for King of Fighters XV following the game’s release?

Oda: We have already finalized some of our release plans for DLC content internally and hope to support the game long-term.

What are your future plans for Unreal Engine? Will we see other SNK titles shift over to the engine in the future?

Oda: We're currently testing a new game in the works that will be using Unreal Engine, so I can say that it's a strong possibility in the future.

With the full release of Unreal Engine 5 looming, what excited you and your team most about the long-term possibilities of next-gen hardware and Unreal Engine?

Tsujii: I'm really excited just thinking about the new possibilities and challenges new technology like Nanite and Lumen will bring to the industry in both the massive increase in graphical fidelity and function.

Were there any particular features of the PlayStation 5 and Xbox Series X/S that helped shape the game or improve how it functions?

Tsujii: Ray tracing works with Unreal Engine, and it's really easy to test on both PlayStation 5 and Xbox Series X/S. After implementing it, it really boosted the game's graphical look.
Image courtesy of SNK
Were there any particular design challenges that the team overcame or elements of the game that you’d like to call out in this interview?

Soranaka: As this game is a continuation of KOF XIV's story, we decided to use KOF XIV's game system as its base. We feel that players accustomed to KOF XIV will be able to transition over to KOF XV with no problems and have fun. In addition to having KOF XIV as its base, we changed some of the systems so that fans of previous KOFs will have fun as well, and so we believe this KOF title will be one that can be enjoyed by hardened pros and new beginners alike. We hope you'll give it a try when it releases.

Thank you for taking the time to answer these questions. Where can people learn more about SNK and King of Fighters XV?

Oda: Please follow us on Twitter, Facebook, or check out KOF XV's website for more information.

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