In reply to the people who asked me about stopping the demo timer, there are two methods. One method is to go here http://modmywhat.com/article/JustCause2DemoTrainer2Released-495 The one problem I had with this method is that whenever I hacked a terminal, it crashed the game. They say that they fixed this, but I haven't tried the update yet so I can't say for sure. The other method involves using Cheat Engine 5.6 (google it if you don't know where to get it or what it is)
Follow these steps to a non timed demo of a game that is to much fun to actually exist in this world.
1) Start Just Cause 2, trigger the timer by jumping off the platform. Press F1 (or 'Back' if you're using an Xbox 360 controller) and check what the timer says. Memorize it.
2) Alt-tab out and start CheatEngine. In CheatEngine, browse the processes and select JustCause2.exe. Choose 'Unknown initial value' from the 'Scan type' drop-down list, '4 Bytes', and hit the 'First Scan' button.
3) Go in-game again, un-pause and let some time go by.
4) Again, open the PDA and check how many seconds have gone by. Alt-tab back to CheatEngine and search for a new value, this time a 'Value increased by...' (or, as listed by the program, 'Increased value by...'), and enter the appropriate value (the time in seconds that passed) in the 'Value:' box.
5) Repeat steps 3 and 4 until you find the correct value, usually an address starting with '1A5'.
6) When found, double-click it to add it to the box below. Freeze it and play for as long as you want.
Note: I did not actually come up with these steps, just found them online, but hey, they work.