What do the different level labels mean?

Most levels have no special label. When a label appears, it tells you about the level’s difficulty or rules:

Label	What to expect
hard	A tougher puzzle with a larger reward.
very hard	One of the most difficult puzzles, with a larger reward again.
quest	A level where you guide the Crab along a path to his home. The introduction shows QUEST LEVEL! and explains the goal.
hard quest!	A more difficult quest level with the largest reward of these level types.
gold rush!	A bonus level that offers a break from harder puzzles. It has no first-attempt reward.
one try!	A challenge level with just one attempt. Read how challenge levels work before you start.