Thanks, I'll add the explanation about the ground to the game's info. As for RP, it is earned by gaining altitude. Unfortunately, in order to save the rp you've gotten during a mission you have to abort before you fall back to earth. So, to gain RP, go up high and then abort the mission. As for the eraser, make sure that after you've placed a balloon and tied it to everything that you want to tie it to, you press 'space' to stop tying the balloon to things. This has to be done before any other tool can be used.