I don't tend to enjoy most remakes since I find them either too different from the original to really be a remake (becoming a different game altogether) or just outright miss in capturing the magic of the original game. This one does neither and it absolutely rocks.

If you're deciding on which game to play, ideally you play the original and then this one later down the line to really appreciate the changes. If you're short on time or don't want to do that, then play this one instead of the first since it does have another spoonful of content added to it. I've included some of the changes that stuck out to me below, light spoilers ahead, but nothing explicit.

---=Changes from the Original=---
-All the old minigames are gone! They ended up removing all of them and instead turned them into simple dialogue trees. There is a single new minigame, but the loss of the old ones is unfortunate.
-All the CGs have been redrawn and there's a small amount of new cutscenes, but most of them are reused from the original game. There's a bit of an odd juxtaposition between the new cutscenes and the old ones but it never bothered me that much.
-Gameplay is based on the later games, and is generally faster than it was before. All the heroines ooze personality on the battlefield.
-All the girls now have small sub stories you can do with them akin to Sakura Taisen 2, that you can progress through during your daily life in the theatre. The rest of the side characters in the Imperial Theatre also have their own sub stories too. They're all great, although Kouran's subplot feels a bit out of character. Speaking of...
-Kouran gets her own chapter! She didn't have one in the original game, so having her have a moment in the spotlight was much appreciated. Its a pretty substantial chunk of writing and extra content and its all wonderful.
-The 5th chapter of the game got an overhaul.
-There's also more romance and scenes with your heroine in this game in general, by a decent amount compared to that original game. Not quite as much as the 2nd one, but everything extra is still good stuff.
-The endings are the same as in the original, so don't go in expecting anything brand new.
-The game is also more connected to the later games, but I wont elaborate on this.
-Shower scenes rock now. I wont elaborate on this either.