"Locked up by the witch"...I solved this by having one pingus bash out, leaving the rest behind a blocker very near the entrance. The pingus that bashes out can jump from island to island...it's a little tricky but I made it on the first try, so it can't be that hard. Eventually he'll walk up the stairs to a spot where he can bash/mine his way back into the prison chamber. I had him mine until he hit steel and turned around, then waited for him to get back to the far wall of the stairway chamber, where you can mine/bash your way to the exit.
At that point you could bomb the blocker to let the other pingus out. I had a miner left over so I let the others out that way and jumped the blocker the way the first pingus had gone, just for the heck of it.
Meanwhile, I'm stuck on Splatterfest...I can't believe they want me to solve this without bashers...