I wanted to post some thoughts on Mercenaries 2 as I am just about 2/3 through it and I think I can speak to it pretty well. The game has been reviewed average at best, it averages a 73 at both Game Rankings and Metacritic. I can’t say that I totally disagree with these scores. That being said the game does have some redeeming values.
I will start with the bad with this game because if you can’t get beyond that the rest of my review won’t help. First, this game is very buggy. I have had a few crash bugs but not too many. There are some really odd physics bugs, like the one in the screenshot of floating (in the air) storage containers. Also the usual clipping stuff but it seems to be worse than recent games in this case. The graphics are just bland, the textures are pretty low res and the poly count on most items is low as well. The story is so thin that it barely explains why you are doing what you are doing. After getting about 2/3 through the game I have seen maybe 30 minutes of poorly written cut scenes that can mostly be summed up to I don’t like these people go blow them up. The last annoyance is enemy mystery boxes that endlessly spawn guys. In some cases the buildings keep spawning guys even after the building has been blown up and is in flames or is rubble. 
Now after beating up on the game I will give it some praise. The game is at its core just fun. Basically this game is a big open world game where you get to run around blowing EVERYTHING up. When I say everything I mean everything, from trees to castles with some ships and lots of vehicles and enemies. There is a huge variety of vehicles including motorcycles, big rigs, tanks, helicopters, jet skis, ships and some cars. I haven’t found anything yet that I can’t steal and drive myself. The driving (flying) mechanics seem to be pretty good as well (even if the controls are silly). The world itself is large and has lots of different terrain and elevation. Once you are in the world there is no loading, the only loading is entering your home base and the various faction bases. While you are running around you have a choice of about 20 handheld weapons as well as calling airstrikes.
Some other quirks are just questionable design choices I think. It is REALLY hard to die, I mean you have to try to just run into a firefight and stand still and get hit over and over. Along these lines the vehicles are pretty tough too and while in them you are invulnerable until they are destroyed. While driving most vehicles you can’t shoot and they have a gunner spot for co-op, but without co-op the vehicle just seems incomplete. The entire map is immediately visible if not accessible. Similarly every objective in the game is outlined in the menu at the start of the game removing what little surprise the story might provide. There is really no consequence to angering a faction since you can just pay them off. One of the factions is on an island which makes getting there annoying if not hard at times.
The final question is would I recommend this game, maybe? If you played the first and like it then definitely yes. If you just want to run around a big world blowing things up then yes. If you want a non-buggy game with any story at all well then pretty much no. The game was in development for a very long time, it started sometime around the launch of the 360 if not before. It seems that they just got tired of working on it and just shipped it out rough edges and all as a result it could have been great but rather is just ehh.
I've been attempting to beat merc 2: world in flames for about a week now, and i must say that, if i had known (from your review or any other) i would have crash bugs every 20-45 minutes i would have spent the extra $10 and bought the console version of merc 2: world of flames. i find the one liners rather humorious on easy though, because i really do just want to blow things up.