--edit from 2020--
I added parts to the "addictiveness" AKA the replayability of the game.

--edit--
Jms please you suck and this review sucks. "small beef" "big beef" IT'S LIL' MASSIF 1 BIG MASSIF YOU DUMB***
I'm rewriting this in better English. <-- Probably bad english but idc.

--original review--

Graphics, Sound, Addictiveness, Story, Depth, Difficulty, Overall?
Well, this game? Pure Amazingness.
And, surprisingly, I didn't make a review about the game. I was like, what? I thought I made one!
Well, because I didn't, I must do it now!
Alright, here goes!

Graphics: 9/10
Compared to a lot of games, this game has amazing graphics, it has natural places, it's luxury & old combined, very well detailed, but there are some cases in which the graphics seems weird.
The best example is before the first giant battle, where Dreambert gets mad, and his sprite gets really big, and his sprite looks like the graphics sucks, that one was.... No. Not acceptable. That's the con of it, so we got 8, but the giant battles sprites... This is just amazing...
And then, graphics has hit 9.

Sound: 10/10
I love the sounds, it has jumping sounds, walking sounds unlike the other games, and amazing songs.
My favorite soundtrack of this game, is Mount Pajama. Big Beef and Small beef, you too haz amazing musics :3 (Notice the bad English? )
If you have the game, and complete it, theres an amazing spoiler I wanna talk about but can't, because spoilers

Addictiveness: 7/10
Uhhh... This game can be addictive, but it is not very addictive to me, as for me: This game is the less addictive Mario & Luigi game. Why? I don't even know! Let me tell you: I DON'T KNOW! D:
This game is awesome and all, but after completing this whole game, it's long, and because the game is hard, it makes me want to not replay the game. Now, I need to complete the game without trying to get hit, and not using any healing stuff. Let me tell you: It's hard
I think that is the reason of why it isn't that addictive, but because of that: 7/10.

EDIT FROM SIX YEARS INTO THE FUTURE: Ever since I wrote this review, I found out about glitches one year later. After I found out, I started playing the game again. I started speedrunning this game and, soon after, got the world record speedrun for the game. My first time being a 7:54:??, back when the world record was 8:12:17. Since then, I have improved my time all the way down to a 4:14:37, with a lot of new glitches being discovered since then. It has become a whole lot addictive since then, putting it at a 10 out of 10 for me. I could talk about the game all day long if I wanted to. Maybe one day the speedrun will go under 4 hours long, who knows? It is currently impossible, but we just need a single more skip and the sub 4 hour dream is real, and it will happen in due to time.

BACK TO ORIGINAL REVIEW:

Story: 9/10
Peach gets kidnapped, saved, kidnap, save, kidnap, save, kidnap, save, kidnap, AND SAVE AGAIN...
No no no no, this is different.
Peach did not get kidnapped by Bowser this time, but this time, it was Antasma. Who saved Peach? Well, you can find that out when you play the game. Antasma is searching for power, and so he kidnaps Peach, by taking her in the dreamworld. Now, it's your turn to save her, again, but a whole story awaits you, and I must not spoil anything. 9/10.

Depth: 10/10
This game is actually short. Wait, 10?
This game is actually long. Wait, didn't you say short?
This game, is weird in length. You only need to do about 5-8 tasks to complete the game, but each task doesn't take 5-10 minutes; but at least 2-3 hours, even in speed running (the first task, too. The first task is actually about 1-1.5 hour, in speed running style) it takes that long, without speedrunning, it'll take 3-4 hours, at the least. Or else, if you skip through text, 5-8 hours. I didn't skip through text, but I just had to read that one text, and I skipped that one text... I was stuck at the same place for 11 HOURS.
It took me 70-80 hours to complete it, much longer then Super Mario World, which has 96 exits. Actually 98 But without glitches, 96.

Difficulty: 9/10
This game is actually difficult, you need to play through 60 hours, and after that you are only level 30, that's what happened to me, I skipped battles, but then, completing it the second time, I was level 40 and it took me 45 hours, it was easier, I knew where to go, and it was simpler.
The text box got messed up, had to copy the whole review, and reload the page. D:
Back on topic, the game is hard no matter what, I still need to aim for 100%. I got all the beans and saved all pi'illos, but now, A couple of spoilers, and some hard stuff... Only after that, I finised the game 100%, and it'll take me long time, and on my first time, I skipped most pi'llos. That's why it was harder

Overall: 9.7/10
One of the best games, but yet, not the best. If you really want to look forward to a good game like this one, check Mario & Luigi Bowser's Inside Story. That's my favorite, most addictive Mario & Luigi Game.
2019 edit: Mario & Luigi: Dream Team is now my favourite game of all time. Thanks!
I love it.
It is a good game, and I definitely like the 2 games, you definitely need to buy both, they are amazing.
9.7 here and there


Well, Thanks for reading my review everyone! This is my longest review, and I really like the game, and you would maybe too Well, guess I'm off again, I had fun writing the review!

Bye everyone!

I'm a huge fan of the Mario & Luigi games and I'm really happy you made this review since it's a game I want to get myself later (but now I'm playing Superstar Saga as I never completed it)
I found it to be useful, but you revealed some things that could be called spoilers. If possible, try to don't give away too much. The rest of your review has your own personal style and I see some inside jokes as well

Now I have some questions and things that I noticed based on your review.
First of all, have you played any of the other Mario & Luigi games? You recommend Bowser's Inside Story but did you play Partners in Time and Superstar Saga? 
Second, you say that a lot of the quests take a long time. What do you see as a part? Until a boss comes in? Or until a certain chapter or part of the story is cleared? I found Bowser's Inside Story and Partners in Time to have this as well while Superstar Saga all has rather short parts tied together into one long game/story.
Third and last, you say it took you a long time to level up since you skipped battles. I recommend to battle as much as possible, as I found myself in difficult situations with bosses when I didn't do that. Although it can be boring it's somewhat an essential part of the game

juuldude :
I have played Superstar Saga, Bowser's Inside Story, and of course, Dream Team.
I might ask for Bowser's Inside Story again and Partner's In Time.
Also, I mean a certain chapter, like, after the first boss, I still count it as the first chapter, only after the second boss I'd say the end of it, which in general took me 1 hour in speed running style.
I skipped battles because I was so exited to play the game and finish it, and I literally played whole days to complete it It took me 5 days to complete it, I got the game on 11 July 2013, a day before it's release date in Europe. I completed it on 17 days.
But when playing the second time, I knew I would have a lot of troubles completing the game if I don't battle enemies, like the first time, so I completed the game again, and it took me a lot shorter to complete it, even with battling everyone, but hey, the first time I did not knew what to do.

Sorry for the spoilers though, I didn't notice it, I'll reread the review tomorrow and edit it. (I'm a bit lazy now. )

That's nice, I never knew about Partners in Time until I wanted to buy Bowser's Inside Story but the game just came out and was very expensive, and somehow I discovered Partners in Time and bought it. Many people state to be the weakest game of the Mario & Luigi games, they also state it to be minor things, which I agree with. You can have a lot of fun with that game as well.

Wait, did you complete it in 17 days or on 17 July? Haha, when you know what to do a game goes a lot quicker but you could try out things you didn't do on your first run like making boss fights more difficults, trying to obtain every gear item and so on.

No problem, sleep well and then you can edit it

juuldude :
Thanks. :3
I have edited out most spoilers, I left in one spoiler in it.
Let me tell you why: Giant Battles is in the first trailer.
So yeah, how could you not know about it?
I didn't really become careful with spoilers, so I'm sorry about it.