This week the 3DS eShop will finally be blessed with 3D classics from SEGA — including arcade classic Space Harrier — but getting these titles to run as perfectly as they do on 3DS was no easy task, as the developers have explained in a recent interview.

Naoki Horii, President of M2, and Yosuke Okunari, producer at SEGA CS3, spoke in an interview with Impress Watch about the long process of fine-tuning and refining a title to create an authentic experience as close to the arcade original as possible.

M2, responsible for porting the 3D Classics range to the 3DS, started life as a small project between Naoki Horii and his friends. Back then, it wasn't easy to simply go and buy a home console version of an arcade game, and, in his words, feeding 100 yen coins into the machines wasn't a great alternative, either. But with a few friends from school and the arcade, they got together to create and build a home console version of the arcade classic Gauntlet. It was such a good recreation that when they took it to the now-defunct Tengen, they got the money and materials they needed and had their first game.

Twenty years later, and M2 and since been responsible for the Sega Ages compilations — known as Sega Classics Collection here in the West — and for re-releasing a bunch of titles on Wii Virtual Console. 3D Space Harrier is M2's third attempt at porting the title, after the PS2 and Wii Versions.

Porting a title onto a new system is not as simple as it may seem, and with every new piece of hardware they develop for, new barriers have to be overcome, meaning that even something as powerful as the PS2 — in comparison to arcade machines of old — could struggle to reproduce something such as Space Harrier without the right knowledge. The PS2 suffered problems with input lag and the sound but thankfully, after a lot of tweaking, these problems were overcome.

Okunari explains that, being the 20th anniversary and having much newer technology to work with, he thought porting Space Harrier wouldn't be a problem, but he quickly discovered that porting titles to new hardware isn't quite that simple:

The ins and outs of emulating things were still being figured out back then. Being new to this, even I thought we could churn out ports pretty quickly, but it turns out that wasn’t really the case. It turns out that since the hardware is different, it takes quite a lot of machine power to emulate these games. M2 is quite fussy about these kinds of things, and they wanted to really get the controls right from the get-go.

After so many years of developing for so many different systems, 3D Space Harrier could just be the definitive version of the game. After encountering some minor control problems on the PS2 version of Space Harrier, and changing the controls ever so slightly for the Wii version, M2 decided that for the 3DS version, they'd address player concerns by putting in 3 levels of movement ranges, so that players can play the title how they see fit. 3D Space Harrier has loads of customisable settings — thanks to years of experience — and everything from minor control changes to the screen size and Harrier's moving area can be altered.

After porting the same title numerous times, you'd have thought the process might have become slightly easier for M2, but Okunari reveals that the Yu Suzuki classic was one of the hardest games to translate to the handheld system:.

Re-making games in 3D is almost impossible. When you take a character sprite that was originally in 2D and bring it into a 3D viewpoint, you have to build the graphic from scratch. So for example, back in the 8-bit era, very large enemies were often displayed as backgrounds. But if you did a simple 3D conversion of an enemy like that, it would end up being on a different plane from the player character and look like it’s out on the horizon. If you want real 3D, then it’s basically the same as rebuilding the game from scratch.

But SEGA and M2 weren't put off by what was set to be a very hard task, and instead decided to just jump in head first and create the definitive version of the game.

Horii explains that in making the title 3D, it's actually easier to play:

We had to recreate the game world in 3D from the graphical depth of the original arcade cabinet, which wasn’t ever made in 3D. There were people who helped and worked with development who’d never played Space Harrier before, and some told me they couldn’t get good at the game. When I asked them what they have trouble with, they’d say it was hard to tell whether objects were right in front of their character or not. Once we had the game in 3D, the same people came back and said “OK, now I get it! I can play it now!” Hearing that made me really happy we went through with the project.

Okunari claims that this may indeed be the last Space Harrier — or at least the last port of the title — and he truly believes it is the best version out there, even if he has to contradict himself:

It might really be the last Space Harrier, or at least the last port. So we wanted to make it the definitive version. When we were interviewed for the PS2 version of Space Harrier II, we said that if you bought the PS2 version, you’d never need another version, but 7 years has passed, and well…turns out there was still a lot of work to be done. (laughs)

3D Space Harrier will be available to download on Nintendo 3DS this Friday for $5.99/€4.99/£4.49, along with 3D Super Hang-On.