Possible Clues:

• Wartime machine repelled a bomb, limiting opening for Germany
• It's mysterious like gamine
• Baffler (anagram of 52-Across)
• It's difficult to get me a gin like this
• A puzzling thing
• Puzzle or mystery
• Machine with gamma for chi when deciphered
• There's a mystery in game
• Has 'e got a Ming puzzle in bits?
• Puzzle found in gem, Ian