I got as far as unlocking Zero Lancer, so far.
The in-game dialogue boxes are translated, but there are no subtitles for things like encounter dialogue (a la Dissidia) - which is a bit of a shame.
Interestingly, one of the non-Japanese characters, Sella, is translated as 'Sarah', but the other gaijin seem to have their names unchanged, so far as I can tell.
It's really neat to note the various character-specific dialogue - not least when it comes to the reactions that Zero Lancer gives to certain others... and what a range of characters give to him!
(I'm not sure Luvia has quite the right idea about what kind of guy Diarmuid is, though.)
In terms of the arcade mode, I did Rider's mission first, and went through most of the 'good' characters first - although I have to say that after going through Gil's mission (which I had left near the end) I was more than glad to go through Saber's route again (as Saber Lily) and kick his smarmy face in!
Shame Zero Lancer didn't have a true story mode, though. (You can play as him in the arcade mode, but has no actual story to it.)
Also, some of the alternate costumes are really cool! Those for Assassin, Zero Lancer, Leysritt and others really ought to have some more art for them.
I guess I might have been kind of spoiled by getting Dissidia last week, but I really wish that there was a Fate game that played like that - but Unlimited Codes is still fun.
It will be interesting to see what those as yet unfamiliar with the Nasuverse will make of it all, though.
Oh, and one other thing - the autosave option is not on initially, so if you want to activate it, be sure to go into the option menu and put it on!
(And one other, other thing - it's kind of sad how there is more about two of Ireland's most prominent mythological heroes in this game than there is in much of modern-day Irish popular culture...)