Hydrogen peroxide powered rocket packs fly for around 30 seconds, because they have a specific impulse of around 125, meaning that one pound of propellant can make 125 pound-seconds of thrust, meaning that it takes about two pounds of propellant for every second you are in the air. Mass ratios are low for anything strapped to a human, so the exponential nature of the rocket equation can be safely ignored.

A pretty hot (both literally and figuratively) bipropellant rocket could manage about twice the specific impulse, and you could carry somewhat heavier tanks, but two minutes of flight on a rocket pack is probably about the upper limit with conventional propellants.

However, an actual jet pack that used atmospheric oxygen could have an Isp ten times higher, allowing theoretical flights of fifteen minutes or so. Here, it really is a matter of technical development, since jet engines have thrust to weight ratios too low to make it practical. There is movement on this technical front, but it will still take a while.

John Carmack

While it's a cool concept and I've played a few MUD's that had permanent death. The reality is that the large commercial MMORPG's want that residual income, meaning that they WANT you to keep playing on and on and on... so if I spent 6 months of my life leveling up a character only to have him die some idiotic death (due to lag, stupidity or whatever) and have a permanent death.. well the bottom line is that I and I'm sure almost any other player would simply quit. It would've been a complete waste of time, not that they are already a complete waste of time but that's another topic... If you are paying for a MMOG service you better have something to show for it after a period of time.. in permanent death no one else will really give a shit if you lived or died, they were not a part of that story so why should they even care? So in the end it'll have little or no value to the players, so no one will play it much less pay for that service. At the very least it would have to be a free service like hardcore on battlenet and with diablo it's easy to level up characters fast (so no big loss) but imagine trying that with Everquest...

So if Everquest did that then they'd lose probably nearly all of their customer base, sure there would be a few hardcore players that would like that but realistically not all of us have 24/7 to play a game to constantly level up characters.

Given that Blizzard is using the trademarks "StarCraft" and "WarCraft" in this very specific market (realtime computer strategy games), their claim that "FreeCraft" infringes on their copyright is reasonable and very likely winnable in court.

So, no problem, just rename FreeCraft to a unique name that clearly isn't derivative of Blizzard's product. And don't be mad that they asked you to do this, because they have the right and obligation to protect their copyrights.

On the other hand, unless you've physically ripped code or content out of StarCraft or WarCraft and put it in your game, any claim that your game is "too similar" to theirs seems absurd and almost certainly has no basis in copyright or trademark law. If you ignore them on that issue, then they are almost certain to go away.

And if they don't go away nicely, the resulting outrage over their persecution of the open source community would almost certainly force them to go away ashamedly.

But if you just cave in, and you fail to stand up for your rights when presented with this sort of threat, then you are certain to lose your rights.

If a person asks you to get out of his seat, you move. If a bully asks you to give up YOUR seat, you fight.