I've been playing a lot of Konami arcade games recently, and I've been noticing a really weird trend. Most shoot-em-up fans are at least vaguely familiar with the story behind Salamander and Life Force. Salamander was originally released in Japanese arcade with a pretty standard item pickup system. When it was released in America, the game was renamed Life Force, and the graphics were slightly changed to give the game a biological setting. Life Force was then given a further overhaul and re-released in Japan, complete with the Gradius powerbar system (which totally didn't work given how the game flowed, but oh well.) This was the version that eventually got ported to the FC/NES.
I'm noticing that this kind of working - especially in between regions - is not unique, and I'm completely baffled for the reasoning behind some of them. A few are pretty minor - the levels in Ajax (the Japanese version) are in a different order than Typhoon (the world version.) That one's a bit weird. There are different versions of Akumajou Dracula (Haunted Castle) which only changes the difficulty. (All of them are still stupid hard, just to varying degrees.)
Some of them go much further than changing how much damage an enemy inflicts. The overhead shooter Trigon (the Japanese version) features a checkpoint system, while the world version, Lightning Fighters (the World version) doesn't. I can sort of understand this - I've never felt that checkpoint system really worked all that way in the context of arcade shooters. It's too punishing for a game that's supposed to let the player see as much of the game as possible for their money. In the process, they also removed a minor weapon, for some reason.
XEXEX got a similar, but even worse treatment. The Japanese version uses a checkpoint, with multiple lives and single hit kills. The World version gives you a single ship with a life bar, and instant respawn upon continuing. Okay. Except it strips out ALL of the extra weapons.
The Japanese version of Thunder Cross has an extensive array of weapons and options to grab. In addition to switching around the level order, the World version gives you full options at all times, and adds a bomb weapon, but completely removes all of the other weapons, PLUS removes the rapid fire ability. This certainly doesn't make the game easier - it makes it far worse.
Taking out features for no discernible reason seems to be pretty common. Certain versions of the Aliens arcade cabinet just don't have the first-person APC shooter segments, arguably the game's biggest draw. There are tons of other differences in enemy strengths and placement too. This makes me think that maybe this version was the initial release, and all other versions are simply revisions, so at least that MIGHT make sense.
The one that's most baffling is an extremely obscure game that was originally released as Devil World. It's Konami's take on Gauntlet, more or less, where two players take on hordes of near infinitely respawning enemies while navigating mazes, searching for keys, and finding the exit. Your characters, by default, are armed with crossbows, and obtain more weapons via another Gradius-style power bar.
A second, updated version, called Dark Adventure, seems like the same game, with the addition of third player to join in on the action. Instead of the crossbow, though, each of your characters starts with a sword. The powerbar is gone, and instead you pick up weapons and power-ups individually. Most of the projectile weapons are gone (the laser and flamethrower made the cut, at least) but instead there's a greater focus on melee weapons, like whips and spears. The game is not remotely balanced for close combat, with enemies closing in on any direction - it takes a deritive but playable game into a totally frustrating mess. Furthermore, it removes the linear levels in favor of a non-linear branching structure, which some levels having multiple exits. A neat idea, but it's also possible to go into circles, searching and researching the same areas to find the same keys to maybe try to make some kind of progress. The game is now a total mess.
So, really, what's the point of all this? How did it occur, and more importantly, why were these done from both a creative and a business perspective? These aren't just alternate modes, toggled with a dip switch - they're completely different ROM sets. They certainly aren't just "easy" mode releases either - in most cases, they're either dumbed down, or in the case of Dark Adventure, mangled to unplayability. Since a lot of these games are so obscure, I'm not really sure if these were re-released in the Japanese marketplace, as a way to pull a fast one on arcade owners (Hey! Buy this new game, even though it really isn't!) or they were for overseas release. If taken from that perspective, it's almost offensive, that a game would purposely be made worse for the gaijin. Or maybe it was just a misguided designer who decided to fiddle with the game balance and ended up with an inferior product. These questions are all rhetorical, of course, but it's something to ponder.