Power-ups, reworked

• A new look: each power-up sits on a coin with a coloured rim. Green helps you, red hurts rivals, blue hits everyone.
• A ring on the worm's head shows each active power-up and drains as it wears off.
• Grabbing a red one fires a missile at every rival; green and blue vanish in a puff of dust.
• Wall hack lights the arena walls green while they are open.