I have some problems with this.
First of all, the new translation. Throughout my multiple playthroughs over the years, I became accustomed to the widely available AG translation. Balrog, one of the recurring characters, had the catchphrase of "Huzzah!" when he would burst onto the scene. It's now replaced with a much less inspired "Oh Yeaaah!!" reminiscent of the Kool-Aid guy. This isn't actually any closer to the original Japanese text in the game, where Balrog says "Doryaa!" which is simply a battle cry with no real 1:1 meaning. Okay, so this is a non-issue, but I believe he was a lot more endearing before. There are also some scenes where Sue and Kazuma communicate through a computer terminal, and the new translation depicts it as "IM chat" with the characters not using end punctuation. While I appreciate the attempt at IM "realism," I at first thought the entire game would be like this since the starting scene opens this way, and really got thrown off. I could go on, since the translations really are completely different, but I'm sure a full comparison can be found online somewhere.
I'm not the only one nitpicking about this - since the game's release in March, there has been a public outcry over the translation, and developer Nicalis has been noted as saying they are considering changing some dialogue for when they upload the European version to WiiWare, as well as patching the US version. It's much ado about nothing, but at least good to see they're listening to the fans, die-hard as they may be.
Next, the music. I utterly adore the original soundtrack, in all its 8-bit glory. Amaya really outdid himself in this department, creating entirely unique tracks that fit brilliantly with the game's theme. There's really not a bad song in the bunch. However....
Updated versions of my favorite songs can't seem to outdo their predecessors. Maybe it's because Amaya wasn't in charge of the new mix; instead, the new arrangements were made by Yann van der Cruyssen, who also did the music for Knytt Stories and Saira, two other indie games (which are fantastic as well). There is an option in-game to revert to original everything, similar to the revamped Secret of Monkey Island Special Edition, but I feel that kind of defeats the purpose of a remake even if it's handy. Overall, I feel the redone music is unquestionably this port's biggest weakness. (It must be taken into account, however, that the game is very small, at only 27.5 MB, though no size constraint was required.)
The one overhaul I didn't seem to mind was the graphics. Cave Story still relies on tilesets to fill out much of the screen, but the pixelated versions from before have all been recreated in hi-def (or at least, as hi-def as the Wii can get - 480p). This is actually very nice, since the art style is still largely preserved, despite being touched up not by Amaya, but Adam "Atomic" Saltsman. It helps bring clarity to some washed-out areas that were too cluttered before, and the extra detail allows additional doodads that weren't visible before, like a calendar in Arthur's house.
My gripes with the new version of the game may be somewhat unfounded, since all of the changes were overseen by the game's creator himself. Perhaps I became too used to the old version to let myself really get acquainted all over again. The storyline is still just as engaging, and the scope of the game is still staggering when you think about the effort it must have taken one man. Ultimately, faults and all, this game deserves your patronage, especially for a mere 1200 Wii points ($12). Buy it - you won't regret it.