Rolling Thunder

History

It is 1986, there are 26,573 game centres in Japan, the highest number in history. The Family Computer (NES) was launched three years ago and home video game consoles are becoming more popular, but the quality of games is overwhelmingly better in the arcades.

Namco releases this action shooter game, in which the main character Albatross catches all eyes. His movements are very finely rendered, with his skinny, long limbs. He looks a lot like "Lupin the Third", from Monkey Punch's manga. Handgun in hand, defeat enemy combatants, escape traps, and rescue your colleague Leila, kidnapped by GELDRA, an organisation that wants to take over the world. It is 1986, a good year to be alive.

Hints

Enter rooms marked BULLET to refill your ammunition. Entering an ARMS room allows you to switch to a machine gun and refill your machine gun ammunition. However, before entering each room, kill as many enemies as possible! Otherwise, you'll get a group attack from enemies when you leave the room!

The game can be scrolled back, and scrolling back two screens can initialise the protagonist. This will get you out of a pinch if you are surrounded by a large number of enemies or if you want to increase the number of bullets in your gun!

The game versions do differ in noticeable ways, such as the title screen and more importantly, the enemy location. So if you manage to finish the main one, try out the others too.

Pixel Cherry Ninja prepared a short video presenting the core. Check it out here.

Technical Trivia

This game system reminds me a lot of the Pac-Mania/Splatter House one, Namco System 1. There are several CPUs working in parallel. As many as four for Rolling Thunder, although the one in charge of playing PCM sounds cannot talk back but only listens to commands. The other three CPUs can share information back and forth. Whenever this kind of setup is present, I fear that the core is going to be hard to make. And that has been the case for this time too. One of the biggest headaches came from the MCU software going through an illegal operation at one point. Ignoring the bad byte seems to be enough to get the system working but my MCU module was flashing the problem and locking up. I looked up at what they did in MAME and they have that offending byte listed as an undocumented operation and have some complex logic assign to it.

Sometimes CPUs perform useful operations when an invalid byte is fed to them. This is normally a collection of side effects that come from the implementation of the valid instructions. Well written software should not rely on those undocumented operations though as this quirks will likely change on the next CPU revision.

A related case is when Amiga 500 programmers use to write information on the upper 8 bits of the address registers because the M68000 would not use them to address memory anyway. When the Amiga 1200 came along and those 8 bits were coming out of the CPU, those games stopped working.

Other Updates

• Fixed Misalinged sprites and SFX are too quiet in Aliens

• Fixed crash at end sequence in Bay Route

• Fixed low music and sound effects in some s16b games

We are looking at solving the problem with graphic layers in the System 18 core. There are a few games pending in that core that keep it as beta but the graphic layers are all messed up at the moment so they are not playable. So expect a mix of S18 and System 86 releases for a few weeks.

Furrtek is still working on finishing the sprite decoder chip used in TMNT2. Part of this Patreon actually goes to support other developers such as him. The JTRIDERS core is kept in beta because we are waiting to include TMNT2 in it. The systems are closely related as you can see from the schematics we developed and published for the TMNT2 board over a year ago. JTRIDERS currently boots TMNT2 (find the MRA file attached). But, sprites are not shown because of the missing chip. Once Furrtek is done with his reverse engineering work, the core will be updated for the following friday. Furrtek's work is crucial to advance the arcade community knowledge and I want to respect his work pace.

Thank you for your continuous support.

Disclaimer: Rolling Thunder and Namco are trademarks of Namco. I am not affiliated with, endorsed by, or connected to Namco in any way.