In a move to limit used sales, Resident Evil: The Mercenaries 3D (in both the US and Japan) will lack the feature pretty much all games with save files have: the ability to delete your saves.
You’ll have one save file, and the game autosaves on it. It cannot be reset. Ever. If you sell the game, that person will have to use your save data, meaning they won’t be able to go through and unlock everything in the game on their own. It also means you can’t go through unlocking things again just for fun, severely limiting replayability for some. You’ll still be able to replay the game and all, but you won’t be able to regain all of the stuff you’ve already unlocked.
It seems to be working well in Japan, with the game only re-selling for about the equivalent of $6, but it’s definitely a major annoyance for the consumer. Haven’t seen how many people in Japan are angry (though I’m sure there are quite a few), but I’m sure this is going to make a lot of American fans pretty pissed.