Unlock Rico's Outfit from Just Cause 2
Have a saved game file from Just Cause 2 on your hard drive. This costume allows you to stunt hijack from a further distance.
Unlock Stuff on Mini-map
Health Shrines - After the second popstar mission, Amanda will appear outside your apartment. Take her on a brief tour of the city (Bam Bam Club and the Temple), ending at the martial arts dojo. Complete the training exercise to finish the mission. You will then be able to call her for a proper date. Successfully complete the date with Amanda (where you take photos of her) to have unclaimed Health Shrines appear on the mini-map. For every five health shrines you collect, your max hit points will be increased by 10%.
Jade Statues - You will meet Tiffany during the "Bam Bam Club" mission. Successfully complete the mission to get her number. Then, call her in the afternoon or evening. Sing a song once you meet her at the Bam Bam Club. Score 90% or higher on the song to complete the mission and have unclaimed Jade Statues appear on the mini-map.
Lockboxes - You will meet Ilyana during the "Important Visitor" mission. You will have access to the mission once you reach 70% game completion. Call her after completing the "Important Visitor" mission. She will challenge you to a race. Beat her in the race to complete the mission and have Lockboxes appear on the mini-map.
Spy Cameras - You will meet Not Ping during the "Listening In" mission. After the "A Big Betrayal" mission, she will call you and take you to an area to hack a camera. Hack the camera to complete the mission and have Spy Cameras appear on the mini-map.
Once you are able to bet in cockfights, go to the arena on the far left of the map. Most of the cockfight arenas have a betting cap, but the one on the far left does not. Save the game immediately before talking to the NPC at the front of the arena. Then, place a bet for the maximum amount of money you have available. If you do not win, simply load your saved game and try again. Repeat this as many times as desired.
Easy "A Slap In The Face" Achievement
Early in the game, you will reach the "Club Bam Bam" mission. Inside the club, you will fight several goons in a room lit with aquariums. Grapple one of the enemies, and drag them to an aquarium to initiate an environment kill with the aquarium. Once the aquarium is smashed, a fish will drop out. Pick up the fish using RB, and use a heavy attack to instantly kill an enemy with it and get the "A Slap In The Face" achievement. Note: If you happen to miss with the fish, you will need to grab another fish; there are two aquariums in this first area.
Easy "Sharpshooter" Achievement
When you have a gun and car, start driving, and initiate a police chase (try crashing into a cop's car). Once the chase begins, wait for a good time to lean out and fire. Then, press LB to lean out the side of your car and aim your gun. This will make time slow down, giving you more time to line up your shots. Shoot the tires to get the "Sharpshooter" achievement. Note: Making quick turns or circling around a cop's car will expose their tires better and give you a more clear shot.
While on foot, start a fight with a cop on the street. Knock him out using some attacks, and pick up the gun he drops. Once cops start arriving, grab some cover, and quickly shoot out the tires on one of the oncoming cop cars to get the "Sharpshooter" achievement. If this is not done quickly, the cops will kill you before you can shoot out their tires. Note: You must shoot the cop car's tires while it is driving; it does not count towards the achievement if the car is parked.