Here are ALL 40 of the achievements including the secret Achievements and what needs to be done to get them. They are worth a total of 1,000 points.

Be Quick or Be Dead (10)
Snipe 50 enemy vehicle drivers.

Eat the Heat (10)
Accelerate and brake at the same time.

Heavy Metal Thunder (10)
Successfully complete 10 action hijacks.

Highway to Hell (10)
Complete 3 different races.

No More Mr. Nice Guy (10)
Make ALL factions Hostile.

Armaggedon It (20)
Destroy 20 buildings.

Balls to the Wall (20)
Beat the Winching Challenge 3 times.

Digital Man (20)
Unlock ALL shop items.

Gone Shootin' (20)
Complete one of Fiona's challenges.

Hail and Kill (20)
Using melee destroy 50 objects.

Holy Smoke (20)
With a grenade destroy 50 objects.

Little Savage (20)
With an RPG launcher destroy 50 objects.

Pipeline (20)
Capture ALL outposts for a single faction.

Shoot to Thrill (20)
Get 25 headshots.

Tattooed Millionaire (25)
Earn $1 million.

Billion Dollar Babies (25)
Earn $1 billion.

...And Justice For All (50)
Verify ALL high value targets.

Damage, Inc. (50)
Use 20 airstrikes in Co-Op.

Everybody Wants Some!! (50)
Play with a Mercenaries 2 developer or a player who already has this Achievement.

Nothin' But a Good Time (50)
From the gunner seat in Co-Op destroy 200 objects.

Partners in Crime (50)
Play Co-Op with a friend.

We'll Burn the Sky (50)
Unlock ALL landing zones.

Wheels of Steel (50)
Come in 1st during a Co-Op race.


Secret Achievements

Dirty Deeds (10)
Achieve maximum Universal Petroleum mood.

Forever Free (10)
Achieve maximum P.L.A.V. Mood.

Island of Domination (10)
Achieve maximum Pirate mood.

Longing For Fire (10)
Achieve maximum Chinese mood.

Ride the Dragon (10)
Hijack the tank in the villa.

Stand Up and Shout (10)
Achieve maximum mood with the Allies.

No Compromise, No Regrets (20)
Battle for Caracas.

Oil and Gasoline (20)
Recruite Eva.

Runnin' with the Devil (20)
Verify Blanco.

School's Out (20)
Complete the tutorial.

The Analog Kid (20)
Recruit Misha.

The Rage 20
Complete 'Rescue Carmona'.

Wild One (20)
Recruite Ewan.

You Better Run (20)
Verify Carmona.

Aces High (50)
Capture ALL high value targets.

Hello, Hooray (50)
Acquire the PMC.

The Hero and the Madman (50)
Completed Mercenaries 2.

Find Eva the mechanic and test drive the custom built monster truck with built in jump jets that she has been working on. Once you've run a check-point race you'll be able to purchase the car from her.

If you want more firepower in the game then complete the following tasks to unlock the corresponding equipment.

Unlock MOAB Bomb:
Complete ALL HVT missions for the Allied Nations.

Unlock Ambassador Gunship:
Complete level 3 of the Helicopter Flying mission.

Unlock Diplomat Heavy Tank:
Destroy the targeted buildings for the Allied Nations.

Each Character has 4 costumes (incuding the default costume). To unlock them for each character beat Fiona's Level 3 challenges: Gun Emplacements, Grenade Launcher, Pistol and Sniper. The Pistol challenge is the easiest to complete while the Sniper challenge the most difficult.

This is accomplished by completing ALL the Outpost missions before you initiate the final mission in Story mode. The Outpost missions must be done first because they can no longer be accessed when the game has been completed and will prevent you from getting 100% completion.

This glitch which will come in useful during the game is performed by parking your Vehicle outside of a building that you can enter. Go inside the building and then exit it and your Vehicle will now be completely repaired with full ammunition.

Whenever you win a level 3 weapon challenge bet at the PMC Villa with Fiona one of three alternate costumes will become unlocked. Bet the maximum money for the level 1 and 2 challenges then save and reload the game until you win. On the level 3 challenge only bet the minimum money.