Surprise Attack

While we were working desperately to complete Golfing Greats or Run'n Gun cores for this week, another team member finished reviewing Konami's PCB for Surprise Attack. The PCB turned out to be a cost-saving version of Parodius Da! The Z80 and PCM sound chips had been removed, as well as their ROM chips, leaving only Yamaha's FM chip connected to the main CPU to generate music. The rest of the system was virtually identical. This was brought to my attention yesterday, so we set out to quickly put together a core based on JTPARODA (the Parodius core). And well, this one turned out to be easy, so we have a new game this week which has come completely by surprise!

Work on the schematic comparison was done on paper, but we will move it now to KiCAD and publish the schematics for this board by mid-September. One thing we realised on the schematics was that shadow effects only apply to the video red component, rather than the whole spectrum. They are indeed used to simulate transparency. You will notice that some scenes look different from emulation because of this. You can confirm this behavior on PCB videos available on YouTube.

The scene below is from the core:

The same scene in MAME looks like this:

I am always delighted when we can improve the knowledge of the systems we work on. Of course we will help the MAME team correct this. But for now, this is only for your FPGA eyes.

History

The story follows John Ryan, dispatched alone to rescue a lunar base and space station seized by terrorists. To clear each area, he must locate and recover every time bomb planted along the way and reach the goal. Set in outer space, the game is packed with sci-fi twists—like huge zero-gravity jumps that flip gravity so you can walk on the ceiling, and enemies that defy gravity altogether.

The gameplay feels a lot like Shinobi. Even the character stance is that of a martial artist, rather than an astronaut. You have to collect bombs across the level -like in Shadow Dancer- and you move between two different horizontal planes, although sometimes the upper plane is the roof, rather than a platform. The character can move while crotching as in Shinobi/Shadow Dancer and the game has that puzzle feeling about the stage design that again reminds you of Shinobi. However, the fast paced second background with stars moving quickly across the screen takes away the calm and tension that most Shinobi stages had. The real surprise is that this game isn’t just an action title. After defeating a boss, a bonus quiz stage begins—featuring multiple-choice questions about space! The round ends after three wrong answers or ten correct ones, but if you manage all ten, you earn a 10,000-point bonus.

The VGM of this game features contributions from the composer of Gradius, delivering an outstanding soundtrack full of memorable tracks. It’s surprising that in Japan, the game wasn’t ported to home consoles until as late as 2024.

Other Updates

JTAJAX core, compatible with Ajax, has now reach maturity and is promoted to public core.