Here is the key to this achievement:
- Must find the breakable wall on every level to enter the cave - total of 15 caves. Levels without a cave to clear:
*** Start level (castle)
*** Boss levels (5, 10, 15, 20)
*** Level 17
- There is a small, reddish “x” on the wall where it is breakable to the cave.
- When in the cave, you must travel from the entrance to the exit for the cave to “clear”. Simply finding and entering will not complete the clearing of the cave.
- If you miss clearing a cave, clear the board and go back though. The cave will reset to be cleared. You can get away with redoing 2, maybe 3 levels before the 30 minute mark is reached - depending on the length of the boss fights.
- On level 19, there is the additional artifact to collect - golden statue - before exiting. It is located at the top right of the cave, behind the waterfall. There is a separate achievement for collections this:
I attempted several methods to make sure on the definition of “clear” - laid out above. Clearing the cave counts towards and must be done for this overall achievement:
Good luck!
Nerd For Truth quoted:
You might want to add that it doesn't pop until you defeat the boss and it happens when the other achievements pop.john kenobi quoted:
If you die in a cave and quit out to restart the level, it will not count.