Dreamcast emulator DEmul returns from the void after 7 years with groundbreaking support for Sega's Hikaru arcade board

Hello ROMheads! Apologies for this issue arriving a bit later than ususal, but it came together a bit last-minute, with a busy work week surrounding The Game Awards keeping me tied up. Our main story today came together last minute, as DEmul emulator developer MetalliC graciously spent some time walking me through his work on the Sega Hikaru arcade system.

If you love Dreamcast-era Sega, this is a milestone worth geeking out over, as it represents half a dozen premium arcade games more or less being playable via emulation for the first time. Technically they have been playable for years in DEmul, but as you'll pick up from this issue's interview, there were lots of issues standing in the way that MetalliC has now gone a long way towards solving.

As a quick aside, Read Only Memo is now getting tantalizingly close to 3,000 susbscribers, not quite a year after I celebrated the 2,100 reader milestone with my last giveaway. It's still totally free and a passion project I derive much joy from, even if the interviews I've ended up doing regularly take hours more work than I originally envisioned pouring into this newsletter. (Oops, couldn't help myself). So if you enjoy ROM and still haven't shared it with everyone you know who digs retro games, emulation, fan translations, pixel art — here's me giving you a gentle poke to share it wherever makes sense for you. I'd love to end 2025 at 3,001 subscribers (and to do another giveaway over the holidays)!

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Now then, without further ado, let's get on with the issue!

The Big Two

1. DEmul is back, and it's now the only emulator to play Sega Hikaru arcade classic Planet Harriers

Wowee, has it been a year for previously unemulated gaming systems suddenly being completely playable. The Hyper Neo Geo 64 was a big deal, of course, and the LaserActive bigger still. Is the Sega Hikaru on their level? Maybe not quite, but it's a notable piece of hardware for a couple reasons:

• It's a powered-up successor to Sega's Naomi, the arcade board that shared its design with the Dreamcast. That made the Hikaru the beefiest thing around for a hot minute at the turn of the millennium, but it was only used for six lavish arcade systems, including Star Wars Racer and Planet Harriers, before being discontinued.
• Due to a manufacturing flaw, it's so fragile that the already-rare boards are likely high up on the endangered species list today.

Both of the above feed into a classic conundrum: a system particularly in need of emulation proves particularly tough to study because it's rare, and the short list of games for it means it's not likely to inspire many developers to reverse-engineer it. But it hasn't exactly been completely out of reach: Dreamcast emulator DEmul, first released back in 2006, actually supported it in a limited capacity beginning in 2013. But when DEmul stopped getting new public updates in 2018, the hope for robust Hikaru emulation seemingly did too.

In the years since, neither of the modern Dreamcast emulators, Flycast or Redream, have done all the extra work required to add support for it. But that doesn't mean no one else has been giving the Hikaru any love.

DEmul developer MetalliC has actually continued work on the emulator over the years, as evidenced by a number of WIP videos on YouTube. But he hasn't put out a single new version of DEmul publicly for seven years... until December 11th, when he dropped a test build "mainly focused on Hikaru testing" in the DEmul Discord.

And wouldn't you know it, but it's now running Hikaru games pretty damn well.

"The main problem with this device — there is almost nothing known about it," says MetalliC. "Even no detailed tech specs and list of supported features, all you may find in the net is just a brief specs translated from 2002 'Sega Arcade History' book... Yes, it was [reverse-engineered] and understood to some degree, and was even not too badly playable in emulator, but still, it was mainly not clear what this thing is and how it works. So, I've reverse engineered games code, guessed a lot of things and summarize with already existing knowledge."

MetalliC clearly has a passion for preserving old arcade systems. He says the latest build of DEmul is actually a byproduct of his primary goal, which has been documenting as much as possible about the Hikaru GPU, which he plans to post to Github so it's preserved. He also contributes to MAME, and to the development of reverse engineering tool Ghidra, which has played a key role in figuring out more about the Hikaru's functioning.

"Usually I'm working with software part, research, creating tools etc., while probing / dumping etc. is done by my friends, collectors, or technicans who have this specific hardware," he says. But as the boards have broken and become harder to come by, his friends haven't been able to help on the hardware side, leaving him to instead analyze game code.

"Previously the reverse engineering was made mostly by analysis of 'input data,' when games code push some data to GPU," which could then be analyzed to determine what it was trying to draw on screen. "I've analyzed game code, functions which produced those data, which input they had, where the game gets input for those functions, which math is involved, which is all possible parameters, etc, to more clearly undertand how it's functioning. Yes, it was possible to do the same in past, but with tools like IDA Pro it was much harder and takes MUCH more time [compared to with Ghidra]."

Even getting to the point where Ghidra was useful for better understanding Hikaru games took work, though. He had to chip in fixes to make the tool work well with the Hikaru CPU's SH-4 code. Once that was done, he could look at some Hikaru games, plus the Xbox 360 port of Virtual-On Force, and pick through the code line-by-line to fix some of the graphical issues that once afflicted DEmul's emulation. That port proved particularly instructive "as it uses a wrapper from original game code to OpenGL and then to Direct3D, so, I've studied from there how they wrapped/emulated certain features," he says.

While Hikaru games were somewhat playable seven years ago, the research he's been working on lately has lead to some major improvements and "almost fully reworked" 3D rendering:

Lighting now is much close to original, it was emulated in prev builds too but was very wrong and barely visible. "spot light" type effects was totaly missing

Fogging distance math is fixed (previously it was hacky enabled for certain objects, but disabled for everything else to not make it looks bad)

"Z-blend" feature is emulated. notable at Planet Harriers 1st stage, when scene objects looks like translucent and covered by clouds/sky background, depending on distance. unique feature of this GPU

Geometry transformation engine is (hopefuly) fully right emulated, so "Hikaru test ROM board" produce good visuals, among with minor effects in Planet Harriers

Texture environment modes/functions correcly emulated

Texture scroll emulated (at Planet Harriers Lava stage lava is moving, etc)

"Motion blur" effects implemented, actually it's just blending of rendered image with previous frame or some 2D image

Vertex processing improved, not draw garbage strips in some scenes anymore

There are also fixes to 2D elements that weren't displaying properly before. Despite all of the above, MetalliC says the Hikaru emulation is just at the point where he'd describe it as "'it looks not too bad and close enough to real thing,' but not accurate," the inevitable result of the guesswork he's had to do without being able to closely study the original hardware. Hopefully in the years to come MetalliC will have the opportunity to achieve the level of accuracy he strives for, too — but for now, the games being far more playable is a huge win.

The current public release, available on Discord, was meant to catch any major issues, but it doesn't signal his work on Hikaru is complete. "Next is planned to implement several UI/UX things for Hikaru, like resolution switching, aspect correction, etc, to make it look not too bad on displays which is not old 4:3, and then do kind of 'official' release," he says.

So that's something to look forward to in the coming months. When DEmul sees its first public release in many years, it'll be by far the best way to play a short list of '99-2001 Sega games unless you're lucky enough to find one that's managed to survive all these years in the wild.

If you do, and it's Star Wars Racer: say hi to Watto for me.

2. Time to put our (odd) money where our (odd) mouths are: Support Hilltop and Milano's Odd Job Collection!

I wrote a little bit about Milano's Odd Job Collection over on PC Gamer this week, but I've got to bring it up again here! This PS1 game on Steam is a rare and precious thing: an opportunity for a fan translation team to work on an official release, and for that release to be the first time an underappreciated old game is made available digitally and playable outside Japan. Cool cool cool — this is the dream pipeline for fan translators and romhackers, to see that work manifest in its most polished possible form, and make the game available to the widest possible audience.

Reviews for Milano's Odd Job Collection on Steam have been 100% positive so far, but only 10 people have left them as of this writing, which isn't enough despite the inevitably niche group of people interested in a slice of life minigame collection first released 25 years ago. If you've played any of Hilltop Works' fan translations over the last few years, time to pay it forward with the $15 this game costs!!!

Regular Hilltop collaborator Cargodin served as the translator for Milano's Odd Job Collection, and if you need a refresher on some of the translations they've both released in the past few years, here you go:

• Racing Lagoon
• Aconcagua
• Dr. Slump
• b.l.u.e. Legend of Water
• Harmful Park
• Dog of Bay

Aaaaaand the ones featured in-depth in this very newsletter:

A summer vacation in November

Long-awaited fan translation Boku no Natsuyasumi 2 is here at last, and it’s glorious. Also: an unreleased Daredevil PS2 game is preserved and playable.

Read Only MemoWes Fenlon

Inside the 10 years it took to translate Linda Cube Again

It took 10 years to translate Linda³ Again, but almost 30 to peel back the mysticism of what this one-of-a-kind RPG is truly about.

Read Only MemoWes Fenlon

It's not often that we have an opportunity to show the companies that lock the rights to old videogames up in their IP vaults that we truly will pay for them. If Read Only Memo readers help get that review number up to 25, I'd be thrilled, and it will be a small but meaningful sign that those of us who love the hobby emulation scene for granting us access to old games will show up when they get licensed, too.

If you need more convincing, check out this livestream featuring Hilltop and folks from publisher XSeed and emulation porting house Implicit Conversions talking about the game!

Patching In

Cemu hits the metal, heavy – After more than a year of work, Cemu's next big update will include a new backend: Metal support for Apple's modern silicon. Some testing at the link indicates performance on chips like the M4 doubling the previous performance on Vulkan. Breath of the Wild on a MacBook Air, anyone?

PCSX2 reports on your dumps – The PS2 emulator has long had the ability to dump game textures and upload your own custom replacements, but it didn't offer a visual indicator of how many it had processed in either direction. That info has now been added to the performance overlay. Convenient!

FM Towns emulator Tsugaru, improved! – I'm pretty sure I've only ever played FM Towns games via ScummVM and DREAMM, but of course it has its own emulator! The developer started it back in January 2020 as part of their ongoing FM Towns preservation work; when they found themself in need of a debugger, they went and built it. The first new release since May includes a speed improvement in High Fidelity mode and for the Yamaha YM2612 sound chip, as well as a graphics fix for the game Microcosm. There are plenty more commits from the past few months on the Github, but hell if I know what any of 'em mean!

Commodore 64 on DS emulator GimliDS gets a big 1.6 update – I know what we're both thinking here: Finally, all that time I'm spending playing Commodore 64 games on my 20-year-old Nintendo handheld is going to be so much better! Why does this exist? Well, why did Captain Kirk climb the mountain? The 1.6 update adds a "50Hz True Sync mode which changes the DS native 60Hz refresh to a 50Hz refresh and syncronizes the emulation to provide a nearly tear-free experience," improves CPU timing accuracy, includes a "major reworking of configuration options," and ensures that Turrican works on the system.

GimliDS only launched back in April as a port of the Frodo emulator to DS, and it's seen some huge improvements since then. Good going, dwarf.

Core Report

MiSTer CD-i core keeps getting better (oh no) – I'm afraid that soon it's going to be hard to avoid playing CD-i games on the MiSTer, a truly horrifying eventuality. But that's the only takeaway from the core's continued progress, including recent unstable build fixes for dual SDRAM and "support for chroma subcarrier for clean composite video from external RGB converters" which will surely be helpful for certain setups. Meanwhile, last month the core got some updates that made for more accurate colors in FMVs and added fast CD seeking, alongside a bunch of fixes.

PSX core goes stops Wiping out – A recent update to the MiSTer PlayStation core fixes an audio looping issue in WipEout and another in Duke Nukem Total Meltdown, among other issues:

• Add old GPU option (Toggleable in misc settings): Simulates GPU (CXD8514Q) from early 100X models (Old GPU crops 8:8:8 bit gouraud shading color to 5:5:5 bit before multiplying it with the texture color)
• Loading screen hang in Disney Goofy's Fun House, black screen in Vigilante 8: 2nd Offense, music cutting out in Arcade Hits Wolf Fan Kuuga 2001

Jotego's Run'n Gun core for Analogue Pocket goes public – The initial release of Run'n Gun for Analogue apparently had some issues, but it's now fixed and available to the public, no Patreon backing required. (You still should, though, if you're a regular player of Jotego's cores, since you'll get access to most of them months early!).

Translation Station

Anime fighter Zatch Bell: Dream Tag Tournament lands in English and Spanish – Talk about deluxe treatment for a fan translation! Early 2000s anime series Zatch Bell, fondly remembered by a subset of Toonami Youth, had a whole bunch of games that never made it out in English. Series fan / hacker SuperrSonic has gone the extra mile by translating one of those games into English and Spanish, making an obnoxious minigame easier in the patch, and offering an optional dub add-on that pulls in about 140 voice lines from the English anime dub to convert a substantial portion of the game's Japanese soundbites into English, too. The cherry on top is a breezy video breaking down all the changes and the work that went into them — wonderfully instructive if you like to see how the sausage is made.

I highly recommend it even if you aren't particularly interested in the game itself. SuperrSonic is also working on another of the untranslated GBA Zatch Bell games, an action RPG, which may be exciting for you Legacy of Goku fans out there.

A PC Engine RPG, for thee? Fortress of Necros it is – This 1990 JRPG is going to resemble a slightly gussied up Famicom game, and is perhaps most notable for having a light connection to the designers of Tengai Makyō and Sakura Wars, Red Company. Actual development was seemingly outsourced, with Red probably just providing some initial design work. This was a licensed game based on a line of toys that came with candy, so probably more in the "historical curiosity" category than "lost treasure."

Willy Wombat, improved – The hacker working on an upcoming translation of Segagaga (stay tuned for more on that project!) recently published this patch, which makes the Saturn 3D platformer a bit nicer to play in English. It already had English audio, but now the following are translated: Title RAM choice, translated options and save/load menus, plus loading

Good pixels

Instead of the usual pixel art, I thought I'd quickly highlight some art that folks dug out of the Video Game History Foundation's recent dump of 200 archival GamePro CDs, full of official screenshots, concept art, etc.

Apologies for Bluesky posts still not rendering in email embeds — I don't know when Ghost is going to make those work, if it's even possible! — but they're worth the clickthrough. 💽

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