What are the differences between the TG16 games "Time Cruise" and "Time Cruise II"?

Time Cruise is a pinball game for the TG16/PC Engine, released by Face. It has a named "II" "sequel", but many things about this arrangement make no sense.

• The games appear to be identical in every way, including graphics, music, and gameplay.

• The "II" version has a copyright date of 1991, the "original" of 1992.

• All art I can find of the "II" version's box art is in japanese, and uses the console name "PC Engine" rather than "TurboGrafx 16".

So this is a multipart question:

• What's going on here?

• Is there a J/E version of Time Cruise 1 that led to a sequel being titled 2? If not, why the numbered suffix?

• Are these games substantially different in any way, or was it just an overseas rename?

It is/was common for games published in Japan to only get their sequel(s) translated and released for English markets. One of the most well-known examples is Secret of Mana, which is actually Seiken Densetsu 2 — the 1st and 3rd entries in the series were never release outside Japan, and so in English we only saw the game Secret of Mana “1”/Seiken Densetsu 2 in English. Another famous example is Final Fantasy IV, which was originally known in English as Final Fantasy II, since Square skipped releasing the original II and III for English markets.

This mostly makes good business sense, even if it's more confusing in today's connected world. After all, they would have been foolish to give English gamers "Secret of Mana 2*" in 1993, since it would have only lead to people wondering where #1 was, and possibly even avoiding #2 if they assumed they would be missing references by not playing the original first. It was just less confusing to renumber games when not every instalment was available in translation.

Time Cruise appears to be one of those games: released as Time Cruise II in Japan, it was localised and released as just Time Cruise when Face wanted to get it into the English market.

However, the case of Time Cruise 1 (J) might be slightly more anomalous, since no evidence of the actual game has surfaced. It appears that Face may have been a victim of their technological ambitions and overly-quick advertising — Time Cruise was advertised in Japan and promised fantastic features, but apparently was never finished or released. As a consequence, it appears that when they finally released a Time Cruise–series game in Japan it was named “Time Cruise II” to distinguish it from their previously-advertised game. Meanwhile in English there had been no advertising of the earlier design and so there were no existing expectations that had to be finessed, so they released as “Time Cruise” directly. There's very little information about the “original” Time Cruise (J), which seems to support the possibility that it never did exist in the first place.