4.20 update — Who move my key? Steam update #1420097

1. Added some text prompts to prevent players from not finding the exit button. 2. Reduced the player's collision volume and increased the coin's collision volume. 3. Optimized the triggering method of Steam achievements. 4. Optimized the coin generation sequence, now reducing the chance of overlapping with other objects. 5. Now supports background mute and windowed mode. 6. Rocket dash can now automatically pick up passing coins. 7. Fixed 2 indescribable bugs.