Konami's 1992 arcade release X-Men probably doesn't need much of an introduction. It was during that year that I happened to be in our area arcade, and someone had abandoned a game of X-Men arcade, leaving Nightcrawler to idle on the screen. I took over the free game, and I was HOOKED.
This game really got around arcades at the time, and it thankfully resurfaced with a digital release in 2010 thanks to Backbone Entertainment. The great thing about this Xbox 360/PS3 release, though, was introducing me to the Japanese version of the game.
On the surface, the only thing that changes is the game places Japanese subtitles in correlation with the voice samples still recited in English. However, peeling a few layers back, you begin to see how the revision tilts the game more toward the players' favor and makes it a more fair - and more importantly, fun - playthrough.
Off the bat, a couple of the changes are extremely evident: The game introduces a pink Sentinel variant and these drop pickups that restore your health or grant you an additional use of your mutant power; and the mutant power orbs are consumed before depleting your health - the opposite of the U.S. version depleting your health and only consuming orbs if you don't have enough health to cash in for the attack.
The big game changer, though, is that the characters have command-based attacks in the JAA version. Players can mash the attack button as usual, but if you hold down-forward or up-forward and attack, the characters execute a few different attacks. These attacks are cycled in at random as the player mashes attack in the U.S. version. Most notably, Storm gains the ability to execute a down-forward+attack move where she extends her wand forward, safely poking the enemies with a long-distance attack.
Then there are tiny differences that add up, such as enemies not being able to be knocked off the screen, and enemies that enter from the backgrounds (walking through doors, etc.) taking a full string of hits instead of being knocked down in one hit and not taking much damage in the U.S. version. The JAA version slightly changes a few enemy configurations, but it also tones down the HP of the bosses a little (notably, The Blob can be knocked down in three hits as opposed to six).
If you are a fan of this title and haven't done so, do yourself the service of playing X-Men in this revised format. The changes don't make the game "free," but you definitely feel like more mechanics are available to you, and you finally don't have to be afraid of using your mutant power sometimes (imagine a character in the comics or cartoon can't use their signature powers because they don't have any "orbs" at the moment).