Just Cause

Hint: Grapple hook:
After level 2 there are territories you can take over. Once you have done about three of them you will get the grapple hook.
Nightmare2917970.

Hint: Helicopter:
When you get your grapple hook fire it at a passing or attacking helicopter. Then, just reel your self in.
Nightmare2917970.

Hint: Agency jeep:
After you kill the man on the boat and finish the mission, you will get the agency jeep.
Nightmare2917970.

Hint: Bald Eagle Persuader boat:
There is a boat that looks oddly like the Gungan submarine in Star Wars Episode 1. It is called the Bald Eagle Persuader. It travels ridiculously fast on water. If you drive it in a straight line for long enough it takes off and wings grow from the side. When you land it, wheels pop out underneath. It is very difficult to control. It appears about one in every ten visits to the mansion near a safehouse. Note: it cycles in this order: sea, air, land. If you go from the air to the sea it will just explode.
Daleboyplayer.

Hint: Taking over sites:
Use the following trick when you are taking over a village with the guerrillas. Ignore most of the enemies and charge towards the roadblock the government has up. Destroy it using grenades, a rocket launcher or timed explosives. Do this to each one, and the "Capture enemy flag" objective will soon appear. Rush to it and press A to conquer that area. For other villages without roadblocks, such as the towns when a police car with a turret on the back appears, go in it. One of your teammates will also enter. Drive down street and your partner will gun down everyone. Then, capture the flag when instructed. Do not open fire on anyone on your team or they will kill you.
typfe rpdhtao.

When taking over Guerrilla and Rioja sites, use your heavy drop in your PDA. Choose the truck and just start shooting your way through the entire thing until you have to take the flag at a Guerrilla site or kill the head honcho at a Rioja site.
flyingkow.

Hint: Boarding the President's plane:
When you are flying the jet in the final level, fly over the top of the plane. Try to hover over one of the wings or the front of the plane (recommended). Quickly jump out of the jet and let go. If done correctly, a "Jump to vehicle" icon will appear. Quickly press A and he will grab on. You will immediately appear in the plane.

On the last mission you will be in a jump jet and other planes will follow you. Go towards the Presidential plane. Fly straight into it and bail out above the wing. If you touch the plane you board it. When on board, kill the black hand and go towards the door. You will begin falling . Fly towards Mendoza and tap A to start an intermission sequence where Rico puts a bomb on Mendoza. Mendoza explodes then Rico says "He always wanted to spread his spirit; and now there's pieces of him everywhere!". You will respawn at Mendoza's mansion and the game will end.
jack yeah right.