Land on a real world and feel what its gravity, heat and air do to you.
WASD + mouse, Space to jump, Shift to sprint. E drop hammer and feather, F throw a rock, X use (beacon or sample), C compare, M sound. Complete a world's survey and return to your lander to unlock more worlds. On touch: left thumb moves, drag the right side to look.
Earth, Moon and Mars globes use NASA maps (Blue Marble, lunar and Viking Mars mosaics).