Explosions are pretty... that's about it. Read on to see what I think is good and bad about Mercenaries.
The Bad:
The air and atiliery strikes were really cool, but the air strike is the only one that is any good. The other strikes are very innacurate. That bad thing about these strikes is that the RPG missile launcher does the same thing, and is ALOT cheaper to buy. There's no motivation or reason to EVER use the strikes when you can get an RPG to do the same amount of destruction. Very dissapointing.
You can blow up anything in the game, even 10 story buildings, but there's never a reason to do it. You don't get the satisfaction out of it because there just isn't a cause for it. For example, if you want to take out a bunker full of enemies, you can attempt to blow the building up, but none of the enemies die. So it's just pretty to watch and it has no purpose or substance. Very very dissapointing.
The missions are pretty lame and don't offer as much action as you'd expect. This has alot to do with the AI's stupidity and lack of challenge. Capturing the 52 bad guys is really easy and is the same thing every time. Never offers anything new or challenging. Can get repetitive and very boring especially when you realize that you can beat the game, and take out any opponent in the game with a standard rifle. The AI is very stupid. The helicopters are less of a threat than a single ground troup, and they fly in moronic patterns and fire very little. Also, the helicopters don't have any firepower except a machine gun which isn't any more powerful then a standard ground troup machine gun. The AI also offers no challenges, and are very easy to take out. You never feel like you need to approach a problem with tactics or stealth. They often let you just run up to a group, stand there and shoot them all. Another example is when you decide to take out an enemy jeep. It has a driver and a shooter. You never feel like they are going to kill you, and you can run up and shoot the gunner. Ok, then the driver will SLOWLY attempt to run you over. I'd expect him to get out, and try to take cover and shoot me. The tanks also don't offer much of a challenge, and you can simply run around them and shoot your rifle till they blow up. Just horrible AI. There is supposedly a stealth mechanic, but I have never seen it happen for me. I also have heard others complain about this. One of the main characters (jen mui) is supposed to be more stealth than the other characters and less likely to be seen, never experienced this. Terrible stealth mechanics. I think this game would be much better if the stealth actually worked.
There's never a reason to jack a helicopter. They arn't fun to use, and have unresponsive controls. The machine gun isn't much more powerful than your standard rifle and I get much more satisfaction from a car's gun. The cars have many different types, such as rockets, grenades, and also standard machine guns. The AI helicopter drivers don't add much diversity to the enemy forces.
You never really feel like you are taking out an entire army. The game doesn't give you any feeling of progression against the enemies.
The extra unlockable stuff isn't very good and it's not very exciting trying to find all the "blueprints" or blow up all the statues. Boring and repetitive, and don't really fit in that well. At least GTA gave you a reason to find all those little things. This game doesn't really make is worthwhile or exciting. I don't have a reason to play again becuase the unlockable stuff is pretty lame. No replayability.
There's a good length to the game, which is a good thing, but all the above factors don't make you feel like you should play any longer than the first few missions.
The Good:
The explosions are very awesome looking. The graphics in the game are really nice.
You can blow up anything.
The shooting system is awesome, and comparable to any other shooter. You can buy just about anything you need, and have it delivered to you wherever you are.
You can use faction specific vehicles to sneak into an enemy base. Not really that great but can be useful.
The best thing for me about the game was:
You can blow up anything, and the explosions look very good.
The worst thing for me about the game was:
Missions are boring and repetitive. Also, the game never gives you a reason to blow stuff up or cause any havoc. The explosions don't have any effects on anything, all that it gives you is something pretty to look at. I'm not even exaggerating here. You never feel like your accomplishing anything and there is no replay value to the game.
I recomend you rent this. It's very worth renting for a couple nights because it was VERY fun for a few hours. But I don't think it deserves a permanent place on anyone's shelf, even if your just a casual gamer.