I really enjoyed all the previous Milleniums, but this one was lacking in comparison. Normally, I would try to find all the animal kings, all the secret rooms, complete all the quests, but with this game, I found myself not really caring and just wanting to get through to the end. Here are the problems I had:
1) This game is extremely short compared to all the other Milleniums, with much more limited everything--sidequests, maps, "dungeons," areas to explore, etc.
2) The dialogue felt extremely stilted. One of the problems was that it wasn't edited very carefully, and there were a lot more typos and grammatical errors. Another problem was that there were huge chunks of dialogue after about every dungeon area. This wouldn't be bad if the dialogue was well-written, but most of the time, it was extremely repetitive, it made me dislike characters (Marine came off, at times, as a whiny, immature brat), and it was also very stilted. For instance, there'd be a long monologue by someone, and Marine would reply something like "okay."
3) Maybe after having my characters knocked back down levels and having to redo all their speed/resistance/strength/mind crap at the guilds every time a new Millenium came out, I just got fed up with it. In fact, none of my characters were as high a level at the end of Millenium 4 as they were when I ended Millenium 3--there just wasn't that much to do.
4) This round, you have to go "bare-hands" like you have to in the actual tournament. Most of the characters, except Benoit and Marine, can't equip hardly anything. There's only 3 sets of armor you get at the beginning of the game that you can equip all your party. You don't even get a 4th set until the end, plus the party is constantly dividing, so after a certain point, I lost the 3rd set from the beginning on someone who left the party for the rest of the game. --Note to developers--it would be very nice if, when someone leaves the party (especially to disappear forever into who knows where) if their equipment automatically was removed from them.
5) Not to mention the fact that Marine and Benoit are the only consistent party members through the whole game. So what's the point of bothering to level anyone when they just disappear for good? I leveled Hirado and lost him. I leveled Karine, and lost her. I started working with Wolverine, then Bear, and lost them both. I was stuck with Bodken, then lost him. . . . Then I got the worthless options of grandpa (forgot his name), the yellow blob and Merline at the end. So, too many characters, too little to do, and characters continually leaving = extreme irritation on the game player's side. :S
6) There were way too many sidequests that relied on you to do X at a certain time, or miss the quest completely. I just found this frustrating. I don't mind a certain amount of those, but given all the other factors, I just sort of quit caring if I completed any. Oh, and just as a warning, don't enter the sewers if you haven't finished up what you need to. As I discovered, unlike with previous games where you can roam around after and complete everything, here you're just treated to a gigantic boss sewer monster, then about half an hour worth of dialogue.
Overall, if you love the Millenium series, then this game is definitely worth checking out to see how the story unfolds. But really, I hope the developers don't do the same crap with the last one (or however many more there will be before the tournament) because Millenium 4 was extremely disappointing.