As Far As I Know...History
Super Street Fighter II X/Turbo was issued in early 1994 with its home ports extending well into 1995. Capcom had a team looking ahead to the eventual Street Fighter III but the landmark title would take significant time to complete. The consensus in the Japanese gaming world was that while SNK was producing a multitude of 2D fighter series, Capcom only had Street Fighter. In rapid succession, the company issued a flurry of new titles and franchises: Vampire/Darkstalkers, X-Men: Children Of The Atom and its sequel Marvel Super Heroes alongside several Muscle Bomber/Saturday Night Slam Masters games, many utilizing members from prior SFII teams. But Capcom also wanted a Street Fighter to tide gamers over until the inevitable III.
Development started in late 1994 and Noritaka Funamizu, fresh off of Children Of The Atom, was once again given the reigns of a Street Fighter title. Surrounding him was a younger, more inexperienced team and he chose newcomer Hideaki Itsuno to lead production. Together they looked back for inspiration. Revisiting the unused Z suffix from Super Street Fighter II X, the concept of origins came about. The name was set: Zero - a return to the beginning and a fitting suffix for a prequel series. Early location tests went remarkably well and Capcom approached Funamizu and his small team with a demand. They wanted the game to run on the CPS1 as well. Future Street Fighter IV and V icon, Yoshinori Ono recalls in a 2015 interview with Wired, "some arcades didn't have as many funds, so it wasn't as easy for them to upgrade. We wanted to make sure these arcade operators could still get Alpha in their hands, so we made a CPS-1 version at a lower cost so they could afford it." Hidden behind that message is the fact that Capcom was sitting on an excess stock of CPS1 boards and needed a way to clear the inventory. With the Super Famicom (SNES) performing well in Japan, the developer decided on a plan: make a quick half-sequel to Street Fighter, sell off the old CPS1 inventory and port the title swiftly to Nintendo's home console. This should entertain gamers until SFIII's eventual release. Simple!
The designers created a hybrid program that would work with both the CPS boards, with main development going to the successor. Coupled with a short development cycle to begin with, reportedly only six months, developers worked frenzied hours. Adding another version to the mix only complicated matters. Funamizu borrowed a handful of developers from other games. Ono continued in the same interview, "I had to work very hard and suffer very long hours of work. The CPS-II team, dealing with really high-quality sound like you'd hear from a piano, they'd come in to work at 6 AM and leave at 8 PM. For us on the CPS-1 team, we were working until midnight every single day and pretty much cursing the CPS-II team."
But that's not all. Capcom also produced specific CPS2 boards they would use for rental (more on page 244). These units would come back to Capcom where they'd replace the ROMs and rent them back out to arcade operators. The company decided they wanted to sell off that stock as well. But that didn't turn out quite how they planned.
Itsuno continues in an official Capcom interview, "Then we had another wrinkle thrown in for good measure. We had to make a version for the rental boards too. We made the sale version, and then we had to go back and make the rental version. So our rental stock didn't go down at all, haha." Instead of diminishing their reserves, they ended up making more. This all but guaranteed a sequel, one which would arrive less than a year later. The Super Famicom version, however, never saw the light of day. The CPS1 release was reportedly very limited, and in fact its existence has not been verified nor has a ROM been dumped. However, the cross-board work would prove fruitful, as the game eventually made its way to the CPS Changer, the for-home unit based on a modified CPS1. Issued just nine months after the CPS2 original, the team's hard work resulted in a remarkable recreation of the original title.
The CPS Changer
While the CPS1 version of Street Fighter Zero never came out, the work was not a wasted effort. In March of 1996, Capcom issued its final title on the CPS Changer home hardware. This was essentially a modified CPS1 board made for home use and it was quite expensive. The unit launched in (when) of 1994 with Street Fighter II' Turbo as a pack-in at the cost of (yen). While two dozen games were planned for the system, only 11 saw the light of day and translations of Street Fighter: THe World Warrior and Street Fighter II' Champion Edition never made it to the mail-order-only service. (v).
Street Fighter Zero for the CPS Changer was issued in Japan only, though publicity builds from the USA and Brazil, dated July of 1995, (v) have been dumped. These were almost certainly made to drum up interest in the hardware but since the CPS Changer was never issued in those regions, it goes without saying interest (fix) was low.
Thus, the work of the CPS1 Street Fighter Zero team was (made something) when the CPS Changer version came out (x) months after the CPS2 arcade board. Since the game was developed concurrently, this version was an impressive rendition of Zero. Some have stated that frames of animation had to be cut, but in my inspection, I have never noticed this. There were, however ,changes to shadows during super moves. The biggest difference was to its sound. While the CPS2 had Q-Sound implemented, the CPS1/Changer did not and the result is more-muffled audio with some samples not being present: like post-victory voices and commentator, "You Win" or "Perfect" sounds. It also lacked stereo sound effects. As stated previously, the music itself was a dramatic step backwards as well. The full soundtrack was later released as part of Street Fighter Zero: Fighters' Generation/Street Fighter: Alpha Anthology as part of its extensive sound-test menu.
Besides this, the game was a fully-featured release of Zero. It contained all 13 fighters, now unlocked without the need of a code, all the backgrounds and endings. In addition, there were a few exclusive perks. By holding down on the P2 controller + the L and R buttons when booting up the machine, you would boot into an alternate menu, now red instead of blue. This is referred to as Ura Mode by some. This opened up a pair of bonuses. The first was the ability to choose your opponent path. This was done by holding down the start button and X before progressing to the character-select screen. After choosing your fighter and auto mode options, you were greeted by four pathways. Unfortunately some of these would crash the game. The second perk was a welcome change to the game's Dramatic Battle. The code from the original arcade game remained, but here two players could choose different characters. Instead of being locked to Ryu and Ken versus the overpowered Vega, you now could choose any two fighters. In addition, you could now play Dramatic Battle with one player (Ryu or Ken only). The CPS2 game only made this available in two-player mode.
Dramatic Battle At the character-select screen
Was That Necessary?
Probably not. I just wanted an excuse to update some stuff and tinker around. Tien Gouki is definitely different and he was the only playable version of Gouki in SSF2X that featured the Shun Goku Satsu. The GameBoy Advance version came out a year later and much later, the HD Remix version was launched on the PS3/Xbox360.