Coin-Op Collection Presents: Twin Cobra (Twin Cobra Platform) / Analogue Pocket Release

I'm happy to announce that Kyūkyoku Tiger / Twin Cobra is out of beta and complete! I spent the last six weeks rewriting the core based on Sky Shark schematics and verified it against my TP-007 (Sky Shark) and TP-011 (Twin Cobra) PCBs. I won't do a deep dive into what was done until Hi Shou Zame / Sky Shark / Flying Shark is released, as it's part of the Twin Cobra platform.

If you'd like to see where we left off, you can check out the initial release here. To summarize what has changed, I finished the remaining GFX requirements for Twin Cobra, made the core fully synchronous, added cheat support, implemented DSP banking, created a PCB filter to model the dual op-amp on the board, and made several other improvements.In the last release of Twin Cobra, sprites were still shifted by one, and tile-flip support for the GLX-01 was missing, which prevented proper screen flip and cocktail mode. The core was also being driven by asynchronous clocking, and I have since synchronized all components to the system clock. The GXC-03 / GCX-04 (TMS32010 MCU) banking caused issues, even in Twin Cobra, because it affected shared RAM writes to sprite attribute RAM. Sound playback was also problematic due to the previous OPL2 module that was being used.I have resolved all of these issues and several others that were present. At the moment, the Analogue Pocket version is superior because there are additional changes I still need to make in the MiSTer version. These MiSTer updates (98MHz SDRAM / ez68k) will follow the same pattern as the Toaplan V1 platform and will be completed after I implement high score saves and release the remaining Toaplan V1 titles (starts tomorrow).Until I have completed the MiSTer changes, you may occasionally see the logo flicker or appear out of sync in Kyūkyoku Tiger / Twin Cobra. This is related to DTACK generation on the M68000 main CPU. The issue is known and already resolved, and the fix will be published with Flying Shark.Now let's cover the differences between the Analogue Pocket and MiSTerFPGA platforms. I will go over the options and cheats below. On the Pocket, you have auto-fire options, and the available cheats include invincibility, infinite bombs, maximum weapon power, and weapon selection. If you are playing a two-player cooperative version on the Pocket while docked, make sure to enable P2 Cheats in the menu.

For the MiSTer version, you have per player auto-fire options, and the available cheats are invincibility, per-player infinite bombs, per-player maximum weapon power, and per-player weapon selection. As always, the standard K3 options are included. Video and audio options are demonstrated in the video below along with native cocktail and screen flip support via dip switches.

I'll cover updates to Midway later this week as I release new entries to the Toaplan V1 platform, starting with Truxton / Tatsujin. I took an extra two weeks to expand Twin Cobra and write a few new Toaplan cores before Pramod and I begin the Raizing / Toaplan V2 revamp and the release of NEC V25 titles.Some of those new titles are pictured below and I've included a summary for Twin Cobra. Assuming Midway doesn't take up the majority of my time for the rest of the month, we'll see them in the coming weeks, just in time for Christmas!Today's release has been pushed to the respective updaters, the files are also available in their respective GitHub repository.

Game Information:

Released in late 1987, Kyūkyoku Tiger / Twin Cobra was a highly popular vertical shooter and a huge success for Toaplan. Distributed by Taito, it ranked as the third-highest-grossing arcade machine in the United States in December 1987 and the fourth-highest-grossing arcade machine in Japan in January 1988. This release was known for being Toaplan's biggest hit in the coin-op market.

Gameplay Information:

Kyūkyoku Tiger / Twin Cobra is a vertical scrolling shooter where players control a helicopter equipped with two primary actions: a main shot and smart bombs. The main shot is used for both air and ground attacks, allowing players to destroy enemy planes, ships, tanks, and certain buildings. The smart bomb, while limited in number, delivers a powerful blast that can clear multiple enemies at once.

If the player is hit by enemy fire or collides with an enemy aircraft, they lose a life and are sent back to the nearest checkpoint. The game ends when all lives are lost. The game spans 5 stages, and upon completing the 5th stage, the player starts a more challenging loop (stages 6-10). This cycle continues until the game is over, with difficulty increasing progressively until the 16th loop, where enemy bullet speed is significantly heightened.

Item Information:

Target and eliminate pickup carriers (large green chopper) to obtain pickup items.

Enhance your firepower:

Collect 'S' to boost shot power and range

Grab 'B' for an additional bomb

Upgrade the TC-7 weapon system:

Blue: Acquire a spreading forward shot

Green: Gain a powerful forward shot

Red: Obtain a wider forward shot

Yellow: Unlock a 4-direction narrow shot

Maximize your score:

Destroy buildings to reveal 'P' stars

Collect these stars for bonus points at the stages end

Regional Differences:

Twin Cobra implements a more forgiving respawn system, allowing players to instantly re-enter the action upon losing a life, rather than returning to a checkpoint. In the event of a tie with a boss, the game skips the landing scene and seamlessly transitions to the next stages music.However, these player-friendly changes come with a trade-off, while Twin Cobra boasts faster ship movement and co-operative gameplay, it reduces the on-screen bullet capacity from Kyūkyoku Tiger's four-round bursts to three-round bursts, these changes alter gameplay strategy and balance.In 1989, Taito released an updated version of Kyūkyoku Tiger that introduced cooperative gameplay at the cost of reducing on-screen bullet capacity. The final version incorporates two new features that could be activated via dip switches on the PCB: a "screen halt" function, which pauses gameplay, and an "invulnerability" mode for practice.Disclaimer: All product names, trademarks, and registered trademarks mentioned are the property of their respective owners. "Analogue", "Analogue Pocket", "OpenFPGA", "MiSTer", "MiSTerFPGA", "Taito", "Toaplan", "Midway" and all derivative works are trademarks, registered trademarks, or copyrighted materials of their respective holders. Use of these names does not imply endorsement or association with this post. All rights reserved to their respective owners. This post is for educational and research purposes only.