I played the demo a while ago and thought it was pretty decent but didn't think much of it after that. Since the Steam deal I've been playing it almost nonstop and I don't really know what to say. I'm in an utter state of awe. Ok, let me try to give you an idea what this game is like:  
 
Take GTAIV 
Put it in an open land mass several times larger than Liberty City with several times more things to do. Also add extensive amounts of verticality in the form of buildings and mountains.
Give the main character the ability to grab onto anything and zoom up to it at breakneck speeds.
Turn up the physics 10x.
Add ridiculous voice acting that is so bad it's good.    
Explosions. Everywhere.

 
What was the last thing I did in the game before I wrote  this post? I chased down a rocket as it was going into orbit with a jet I stole and blew up the projectile in midair several miles above ground level (there is no transition from air to ground so the scale is absolutely GINORMOOUS), then I flew through the insanely good looking explosion and ensuing puffs of smoke (it was so glorious I didn't even take screenshots, and I take screenshots of everything), after which I lost track of my orientation and starting shooting straight down to the ground at Mach 3. When I realized what was happening I opened the hatch of the plane's cockpit, jumped out and spread my parachute as I watched my plane explode in another impressive fireball on the buildings and streets below me, escaping a gruesome death by mere milliseconds and inches.  
 
The surrounding militia were a little pissed that I crashed their plane right in the middle of their hometown after destroying their billion dollar rocket, so they started flipping their shit and a half dozen military Tuk-Tuks (you read that right) stormed my landing location; but they were in such a hurry that they started running over both each other and the civilians, which created enough of a distraction for me to grapple onto an old man's jeep so that I could parachute jump off of that onto another dude's quad bike and make my getaway driving through a dense forest like a madman and barely missing like a hundred trees. Helicopter started chasing me so what do I do? I grapple that bitch, punch the pilot 3 times in the face and throw him out, then I fly that helicopter to the tallest building in the game and enjoy the view.
 
Just Cause 2 is filled with such scenarios, and most importantly they stem from your own creativity. 
 
Games with such open-ended gameplay, physics and environments must look like crap to compensate right? Wrong. 
 

I really liked this game, however the flimsy ragdoll physics turned me off quite a bit. This game would have been awesome if it would have used that Euphoria thing.
 
Nonetheless I've spent many hours playing this and I agree with what you're saying.

I got bored quite quickly and the land size made travel a chore on anything but a jet.
It's not filled with awesome scenarios. There are a few awesome scenarios and the rest is repetitive garbage.
If anything the game is overrated.
2c

I didn't find the gameplay fun, but the open-world stuff was good and the game was fun as hell. Personally I think Halo Reach is the most underrated game of the year as it isn't even being discussed for game of the year at most sites, and is losing to Black Ops for best FPS everywhere (which is ridiculous by the way). Its not my game of the year, its fourth for me behind ME2, RDR, and AC:B, but its a great game with no real flaws. It deserved higher scores than it got. 

You know, I liked Just Cause 2. I really did. But playing on a console made it get really old really fast. Some of the mods on PC have been awesome and that makes it a lot more fun to play.
Also, as a completionist, it was a total nightmare. I spent around 18 hours doing faction missions and completing locations for the 100 locations completed trophy and eventually just got sick of the game.

Like most decent games, I'm entering the ring a bit late. 
Like the author of this thread, I found the demo (the first time) to be a little odd. I didn't like how the parachute and grappling hook were controlled. I hated the driving. I thought the A.I.s where a bit stupid and I was frustrated since there wasn't a cover button. That was under a year ago, probably about a month before the game was released. Last week I re-downloaded the demo and had such an amazing time. 
In a lot of games I own, I am used to following a linear path and only being able to destroy certain, scripted objects. I was used to very boring gameplay. But now I realise the game isn't as shit as I thought, the explosions are so unrealistic it's great. The grappling-hook-parachute-transportation was a breath of fresh air, no pun intended. The fact I could lose half my health bar to a rocket firing helicopter and then grapple onto it, hijack it and then blow everything in site up.... it was great. 
 
Also nice description of the gameplay, I like to think of it as GTA IV, Crackdown 2 (known to have the most ridiculous explosions EVAR!) and a bit of Prototype, all merged, hyped up and filled with even more explosions (GTA, CD 2 and Prototype are pretty much filled with a lot of explosions).

I liked Just Cause 2 with the Bolo patch a lot. The story mode was meh, but dude, flying around in jets and toying with the tether took a really long time to get old. It's also very well optimized, even my 3 year old PC runs it at very high settings at a pretty solid 60 fps. 

Just Cause 2 is amazing and a crazy amount of fun, but it doesn't deserve a very high spot on the list for GotY proper. If you try to do all the side stuff, you will get burnt out before getting through a lot of it, and the story stuff is just kind of all of the same. Like Split/Second, it's a very quick burn that wows and amazes at first, but doesn't hold the same satisfaction the 60th time you do something.

Definitely a great game, though. I know I loved it. I just got really burnt out doing the side stuff, and the story missions weren't particularly good.

" I didn't find the gameplay fun, but the open-world stuff was good and the game was fun as hell. Personally I think Halo Reach is the most underrated game of the year as it isn't even being discussed for game of the year at most sites, and is losing to Black Ops for best FPS everywhere (which is ridiculous by the way). Its not my game of the year, its fourth for me behind ME2, RDR, and AC:B, but its a great game with no real flaws. It deserved higher scores than it got.  "

i was never really able to get into it tbh. I mean i thought it was ok, but nothing amazing. 

you forgot one thing! its only $18 now!!

I got ultimate frustrated and ragequit on one mission and then never went back to it.  I think it was something to do with a limo.  Game was pretty good before that.

The first 2 hours are really awesome.
Then it quickly falls off into chore town

I LOVE this game so much and everyone I know who's played it seems to love it. Just last night I was at a friend's house. We were playing COD, but after dinner I put in Just Cause 2 and handed him the controller. He was still playing and laughing his ass off at the batshit crazy stuff going on at one in the morning. Probably the funnest game I've played all year.

I haven't played that many games from 2010, but Just Cause 2 is very good. I think the worst thing about it is the repetition, and there are much worse flaws to have.

Love the game so much I even went for S-Rank. Definitely one of my favorites of the year!

Had it from day one and I still play it. If that isn't an endorsment I don't know what is.

No way. Don't get me wrong, its a good game. But Alpha Protocol seems much more deserving of this award.

Just Cause 2 = Sandbox game on steroids.

" No way. Don't get me wrong, its a good game. But Alpha Protocol seems much more deserving of this award. "

I played it with the sound off, listening to my music. Guess why? In this day and age, GTA4 and RDR have something Just Cause doesn't: A great fucking story. 
 

I would rather play on a reasonably large area with stuff to do and a great story than an enormous landmass with shitty writing and nothing to do after 2 hours.

I had almost EXACTALY this same experience last night. I blew up that rocket and flew through the explosion then started doing bombing runs over a pipeline blowing up dockyards and I flew underneath a bridge and crash landed at the last second watching my plane blow up into the woods in a glorious fashion.
 
The game is amazingly silly and fun. It looks amazing too and runs much better then I thought it would.

This game got so tedious after five minutes. Definition of grind.

" I played it with the sound off, listening to my music. Guess why? In this day and age, GTA4 and RDR have something Just Cause doesn't: A great fucking story. 
 

I would rather play on a reasonably large area with stuff to do and a great story than an enormous landmass with shitty writing and nothing to do after 2 hours.

"

Every time I hear about this game I want to check it out.  I will most likely pick it up when it's budget price.

" I played it with the sound off, listening to my music. Guess why? In this day and age, GTA4 and RDR have something Just Cause doesn't: A great fucking story. 
 

I would rather play on a reasonably large area with stuff to do and a great story than an enormous landmass with shitty writing and nothing to do after 2 hours.

"

Just thought I'd post some video clips as well (these aren't mine): 
 
  

It was fun at first but it got old fast for me... 

I liked it, but it got a little stale after playing for some time.  I traded it back in to help pay for Fallout: New Vegas and Call of Duty: Black Ops.

Just Cause 2 is a great game and a really fun time, but it does something that insures it will never be considered for any GOTY awards:
 
It doesn't take itself seriously. At all.  So it instantly gets discredited.
 
Critics like games with "mature" stories like Halo, COD, RDR, and Assassin's Creed.  LOL.
 
It's the same reason Bayonetta won't be considered.
 
Polish>Tone>Gameplay when it comes to game of the year.  Or perhaps I'm just being too cynical.

This is looking like it might be a 2011 purchase for me.

Naw...  Just Cause 2 just wasn't that good.  Like the other people that seem to be voicing their opinion in this thread, I found the first little while to be quite fun, then tedium set in and the urge to keep booting the game up died out.  I didn't even finish the story.

Imho Just Cause 2 was a shit game that was fun because of all the shit.. sort of. I think all the shooting feels bad, the driving's okay, but all the bad is balanced up by all the craziness that goes on.
 
The reason why I disagree with it being "the most underrated game" is because pretty much all the fun comes from the things that you do, not the things the game have you do. I think that is on even footing with Dead Rising 2. Could be very boring, but if you make it fun, it's very fun. I guess what I'm saying is that if you think Just Cause 2 is the most underrated game of the year, you might aswell give yourself the "most creative player of the year"-award.
 
Edit: apparantly I type bad at night.

I liked JC2 alot but it really got to be very tedious

" Just thought I'd post some video clips as well (these aren't mine): 
 
  

  
 
 
 
"

This is the one game I rented this year and still didn't play. I wanted to, but I had also rented another game, and Blockbuster is back to only giving you 5 days with rentals. Such a shame. I'll have to make sure I really get some good on-hands time with it soon.

" @blacklabeldomm said:

" I played it with the sound off, listening to my music. Guess why? In this day and age, GTA4 and RDR have something Just Cause doesn't: A great fucking story. 
 

I would rather play on a reasonably large area with stuff to do and a great story than an enormous landmass with shitty writing and nothing to do after 2 hours.

"

I think you missed the point of the game. "

I think it got a lot of praise already for being so crazy.  

I'd get it if I had a PC that could run it. The possibilities are crazy on PC.
 
@trophyhunter said:

" @nintendoeats said:

" No way. Don't get me wrong, its a good game. But Alpha Protocol seems much more deserving of this award. "

Damn straight "

" I got bored quite quickly and the land size made travel a chore on anything but a jet. It's not filled with awesome scenarios. There are a few awesome scenarios and the rest is repetitive garbage.If anything the game is overrated. 2c "

Yeah it's pretty great, but I'm not sure everyone will recognize it's greatness since most people probably played the inferior console version.

A) I think we all know what Just Cause 2 is by now, you didn't need to describe it to us. 
B) This game isn't underrated at all, it got alot of attention and recognition from gaming publications.

" The first 2 hours are really awesome. Then it quickly falls off into chore town "

"

Just Cause 2 = Sandbox game on steroids.

"

Is everyone kidding about   Alpha Protocol? Jeff gave it 3 stars and it didn't look that great...