What is the difference between indoor and beach volleyball?

Indoor vs beach, side by side:

Players: 6 vs 2 per side
Court: 18 × 9 m vs 16 × 8 m
Sets: best of 5 to 25 vs best of 3 to 21 (third set to 15)
Block touch: doesn’t count vs counts as a touch
Tipping: open-hand tips allowed indoors; in beach you must use knuckles or a closed hand ("poke")
Positions & rotation: strict indoors; beach has no fixed positions, only a serving order