Extra Information (I couldn't fit everything there, so i put it here):
Stamina Points will drain even if the Player has stopped running, so no cheating the System. Of course it only drains if u ran while it was still consuming the point.
JBucks are like a Normal Currency, you earn some for specific Stuff that you do, like killing an Enemy or using an Item, surviving something or other Stuff.
Re-run Points are earned for surviving.
You will get 3 every 8 Seconds you survive (That would mean u have to play 800 Seconds for 300, which is 13 Minutes and 20 Seconds, a Round takes about 5 Minutes, so 2 to 3 Rounds are enough to unlock Something at the default Price).
Special Gems are earned for Special Stuff like Achievements (Yes they will exist), survivibg a Delta or Epsilon Level Threat (5 for Epsilon, 20 for Delta and 30 for a certain Delta one... more in another Deck)