No, not unplayable as in it's so bad you can't play it. Square-Enix's RPG, which was just released in Europe, is literally impossible to play due to an error involving its required Steam activation.
Something must have gotten lost in translation along the way during Square-Enix's communications with Valve, because thanks to an error relating to The Last Remnant's Steam release date, the game, which has just come out in Europe, is impossible to activate.
The Last Remnant requires Steam to activate and play. Users have to punch in a registration code on the back of the manual to get the game to work. There's no problem with the code. The issue is that the game - which will be Square-Enix's first on Steam - isn't due on Valve's digital distribution platform until April 9th and therefore cannot be activated.
"The Last Remnant has not been officially released, and cannot be unlocked at this time. Please check Steam news to find out the release time. Steam will notify you when the game becomes unlocked," Steam will tell you if you try to install the game.
The Last Remnant on PC boasts a few new features not present on the original version of the game, including the ability to switch between English and Japanese voice tracks, improved animations, and faster battles. If you Europeans really want to get a taste of the game, check out the demo at the official site. Otherwise, maybe hold off on buying it until Square-Enix or Valve fixes this up.
UPDATE: Well, sounds like the problem got fixed as soon as Square-Enix was able to open up their office and boot up their computers, if this Steam forum thread is to be believed. If you weren't able to get it working before, all you need to do is restart Steam and it should activate just fine. Kudos to the dedicated gamers who braved the wiles of customer service to solve this problem!