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.
lyvtrbwtNightmare2917970.

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

Hint: Taking over sites:
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: 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.