You are correct, this topic caught my attention quite thoroughly.
Ys Origin uses a modified version of the Napishtim/Felghana engine, yes. It's a bit of an "experimental" Ys game, though, which has caused quite a few series fans to shun it. Personally, I think it's quite good, but I actually prefer both Napishtim AND Felghana.
When I say it's experimental, it's for two reasons:
(1) The game takes place 100% inside the Tower of Darm. There are no towns, and for the most part, it's a completely linear experience -- while there is limited exploration within the individual floors of the tower, you're literally climbing from the bottom to the top, so there's never much of a question where to go next, and you rarely revisit places you've already been. In this sense, the game actually reminds me of an old-school Castlevania, pre-Symphony. It's almost arcade-like, with every few floors of the tower serving almost as a unique level -- the water area, the fire area, the desert area, the poison area, etc. There's generally a mid-boss halfway through these areas, and a big boss at the end, with copious story-advancing cutscenes interspersed throughout (it's probably the most talkative Ys game in that sense, with one of the most complex storylines and one of the largest casts of characters).
(2) It's the only Ys game with no Adol (except as a bonus battle arena character, anyway). Story-wise, it takes place 700 years before the events of Ys I, and you actually get to choose your protagonist. When the game begins, you have a choice between Yunica Tovah (who plays ALMOST exactly like Adol in Felghana, except with an axe instead of a sword, and a lightning skill instead of an earth skill) and Hugo Fact (who plays like the Vic Viper in Gradius, complete with options that follow his every movement; closest English-language Ys equivalent would be Mishera from Ys Seven, but Hugo is much faster and has Felghana-like unlockable abilities used both for combat and for exploration, including landmines and a floaty bubble thing), and both of them have slightly different "recollections" as to what happened in the tower, Rashomon-style.
Once you beat the game with both of them, you gain the option of playing as a third protagonist who's initially known simply as "The Claw." He's a super-fast melee fighter with Wolverine-like claws, who has the ability to turn into an even faster demon that kinda looks like the badass male equivalent of Terra's esper form from FF6.
The Claw's route through the tower is significantly different from Yunica's AND Hugo's, and is considered the "real" story (the "here's what ACTUALLY happened" part of the Rashomon tale), with the real final boss and the real ending.
In answer to your other questions, the game is ONLY currently available for Windows, so that's really your only option option for playing it at the moment. There IS an English patch in the works, but it's not done yet; and spec-wise, most computers should be able to handle it, though only really good graphics cards can handle all the dynamic water effects and such (you might have to turn those down if you have a lower-end graphics card).
As for a port, it's really more a matter of time than anything else -- Falcom already has the groundwork in place for something like that, so I see no reason why they wouldn't EVENTUALLY port the game SOMEWHERE. My guess is the NGP will end up getting it, but we'll see. I don't believe it was anywhere near as successful an Ys release as Napishtim, Felghana or Seven, and it definitely sparked a lot of fan ire due to its atypical design and lack of Adol, so its lack of popularity may make the inevitable port take a bit longer to come to fruition than we're expecting... but this is Falcom, so I have no doubt it'll come eventually. (:
No relation at all -- that screenshot and magazine ad are from Falcom's Dissidia-like fighting game "Ys vs. Trails in the Sky: Alternative Saga," which was released on PSP last year. As the name implies, it's a fighting game featuring characters from Ys Seven and Trails in the Sky, with support characters from other Falcom properties, and something like 150 music tracks from pretty much every Falcom game you can think of. The story mode even takes place in the land of Xanadu Next! It really is pretty much Falcom Fanservice: The Game.
Gameplay-wise, the battle system is based on Ys Seven, but with added jumping abilities that (IMHO) make things way more complicated than they need to be, and really make me wish the PSP had just ONE EXTRA BUTTON somewhere.
It's a pretty OK game overall, though. Its story mode has spoilers for Trails 2, however, so if it were to see an English release through XSEED, it wouldn't be for a while yet.
Falcom's been getting fan requests for an Ys IV remake for years now, and I'm quite certain it's somewhere on their to-do list. I anticipate that'll happen sometime in the future, and Ys V would surely be close behind.
In the meantime, you can play either version of Ys IV fan-translated (I recommend "The Dawn of Ys" for the PC-Engine CD, but "Mask of the Sun" for the Super Famicom has its fans as well), and it looks like the Ys V fan-translation project is NOT dead, as Gideon Zhi posted a new screenshot of it on the Ancient Land of Ys message board EARLIER TODAY.
So yeah... good news there!
Any other questions? (:
-Tom
As far as I know, the only port the game got was for the N-Gage of all things. 
