JOTEGO
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The Game with Three Names
🕑 Added 2024-12-31 13:51:19 +0000 UTCHistory
Devil World in Europe, 魔獣の王国 Maju no Okoku in Japan and Dark Adventure in North America, where the game system was significantly changed. This Konami's 1987 game was developed by Hiroyasu Machiguchi, who worked on "Gradius" and "Life Force", together with other members of his team.
The story is about an archaeologist professor who discovers an ancient coffin. The lid of the coffin was to be opened in front of a large crowd of TV and media people gathered to cover the great discovery of the century. But when the lid is opened, it becomes the entrance to a demon world, and the Professor Condor, the reporter Labryna and Zorlock, a young archaeologist, were taken to the Demon world. Can they defeat the Demon King and escape from the Demon world?
The Japanese and European versions are shorter, and also have a nicer gameplay with a weapon system similar to Gradius. But only two players. In the American version, three people can play at the same time. This is also different in the prologue scene, where the third character appears only in the American game. For the US market, the power-up method is no longer a gauge-based system but an item acquisition system, and the player's initial equipment has changed from a borgun to a sword and a shield melee weapon. The number of continues was set to unlimited, which was possible even during the last boss battle, but lives decrease quickly over time and the game inevitably had to be continued to keep playing. It was a pity, but it was obvious that the aim of the arcade game production company was to make you consume a large amount of credits.
If you are new to this Gauntly-style title, try out the Japanese or European versions first. If you grew up in America, you may prefer the local version but check out the other ones too as they are very different!
The Hardware
This is a large, two-board system. This is unusual for Konami, that makes single-board games most of the time. The video logic takes several gate-array chips, rather than the usual two we have seen in older and later Konami systems.
What puzzles me about the system is the choice to have the all the scroll tiles and part of the sprites stored in RAM. The CPUs, mostly the subsididary M68000, is in charge of updating the RAM chips with graphic data from its own ROM chips. This is a process akin to what game consoles did at the time, but the point of doing it on an arcade is not clear. There are some tricks that you can do if the graphics are in RAM, as you can edit them on the fly. A good example of editing tile data to achieve effects otherwise impossible is how games on the NES created the ilusion of having 2-layer scroll, or even more, by shifting around the tile data. I think Konami realized that the cost of the extra CPU was not worth it and this RAM-based approach was quickly dropped. The western version of Hard Punch and MIA are made on hardware with ROM-only gaphics.
Another interesting feature is the use of scroll registers to move all sprites around. On most 2D systems, the CPU stores sprite data on a table with X,Y coordinates for each sprite. When the background moves, the CPU must update the coordinates for the sprites that move along with the background. This can be very tiresome for games that use sprites to draw part of the background. Twin16 approach is to have two scroll variables that get subtracted from each sprite X,Y coordinates, so the whole image (background and sprites) can be moved around more easily.
The Core
We close 2024 with JTTWIN16 beta, compatible with Konami's Twin 16 titles. Skutis, one of Patreon directors, is particularly fond of this system and he has extracted the schematics for all the gate array chips. If there is something wrong in the core, I am the only one to blame because thanks to Skutis all the information about this system is out there for those brave enough to navigate all the system schematics.
The system supports two games already convered in different versions:
MIA (Japan) (Western version supported on JTTMNT core)
Hard Punch (Japan) (Western version The Final Round supported on JTFROUND core)
But there are two new titles:
Cue Brick (Japan), currently the core does not display the sprites correctly
Gradius 2/Vulcan Venture, sprite collision fails badly
Sadly this core does not fit in MiST/SiDi due to internal BRAM limitations. The core is available for MiSTer, Pocket and SiDi128.
Other Updates
JTWC, compatible with Tehkan World Cup, is promoted to public version as no more issues have been reported
JTFROUND, has received the improvements made to the 00788X chipset for JTTWIN16. An important difference is that sprites were visible one-frame ahead of time in the previous version
Although I had planned to make a 90's game from my own favourite list during the Christmas season, I realised I still had a large backlog of promised items so I went for JTTWIN16 instead. There is another debt that I plan to pay during January and then I want to go back to System 18 and figure out the layer priority system, which is holding the core as a beta and keeping a few games unreleased.
Happy new year and see around in 2025 too!
Comments
ElloMrChris
Are Cue Brick and Gradius 2 missing for the Pocket? I don’t see them in the Twin 16 core at all.
Daniel Thomas Stack
Happy New Year, thank you for continuing your amazing work.
Mark Saunders
Thanks team JT - here’s to a happy and peaceful 2025 ! The speech in this title makes me laugh, condor and Labryna 💪
Bit2018
Happy New Year everyone!
8PercentAndroid
Happy new year! Probably being dumb but is Gradius 2 now available in beta?
Fred Jorge Silva de Souza
Great Jose! Happy 2025 with more core consoles and MiSTer games!
Lu's Retro Source
Happy new years! Nice new years gift your giving us!
David Rey
Gracias por todo el trabajo, y la aportación a la comunidad. Feliz aňo nuevo!
Mat Kraemer
Thank you! Gotta love the live action Konami Arcade marquee for Dark Adventure.
Ulf Skutnabba
Thanks alot for oerhaps the most interesting and one of the best arcade platforms of all time.
Hiddenbyleaves
Awesome!
Pixel Cherry Ninja
All the best for 2025 🎉
nuxvomo
Awesome update! Keep up the great work. And happy new year!
Juan Carlos Pastor (Denymetanol)
Felíz Año Nuevo, tremendo regalo, un abrazo familia, acabadlo de pasar lo mejor posible y pronto arrancamos 2025 ^ ^
JOTEGO
Esperanza no trabaja para JT desde marzo 2024
Syl
Thank you so much for your work, happy new year!
Roberto Lari
Happy New Year! Jotego for me you are one of the best on FPGA scene!
Daniel Bauza
Happy new year! Thanks much for your work!
Findamember
Thanks and all the best for 2025
Matt Levine
Thanks for a fantastic year Jotego and wish you and your family a happy and healthy ‘25.
Dr. Manga
Feliz 2025 a Esperanza, al resto del equipo y a tí José
Álvaro Vizcaíno y Hermosilla
Feliz año, portarás cores a Neptuno plus?
AlxUnderBase
Happy New Year 🎊🎊🎊 Thanks for opportunity to use Twin16 games on MiSTer , Jotego & the team and to Skurtis ! I have Vulcan Venture from 2021 , but is on repair from then due the faulty 07778 ! Im waiting the day when a replacement will be made by someone ! With that faulty chip , my pcb make this : https://youtu.be/2sK324s5kww?si=X4v6Y6t9OMR9__Y5
Oliver Jaksch
Woah! Thanks a lot, pal! JTtuesday today - all the best for the upcomin' year!
Filip Kindt
Happy new year
Adrien Duchemole
Thanks a lot Happy new year 🎉
gg heenok
magnifique !!!! bonne année a tous !!!
Lukas Schaper
Thank you! Happy New Year!
Daniel Casadevall
Gracias como siempre y feliz año, José!
Bedwablackburn
Devil world is one I fondly remember playing in an arcade growing up.
yomitron
👏 Take a break. Enjoy the new year. You and your team deserve a respite after all your hard work this year. Cheers 🥂
ronalvel .
Muchas gracias por estos juegos!!! Me encantan los 80s, Feliz y prospero año venidero!!!!
