I hate it when you need to use Firefox for that. There is no purpose for that game. Nothing to do when there appears a really useless screen telling me to get Firefox Really? HELL NO! Firefox is the worst browser I've ever used. You don't need to make your games unplayable. Please. I'm rating this a 1/5 and will never play your games. EVER. again. UNLESS THIS IS SOLVED!
Don't want any of your survivors to die in Impossible mode? The save game button is your best friend, think of when a mission fails and someone dies, that way you can exit and load your save slot, and change missions for the survivor who died to prevent it from happening again.
Can yo get to 5 million and 10 million in altitude? Yes you can, play on Classic Mode, because there are absolutely NO obstacles that may interfere with your trip to the beyond.