showstopper

Noun

 * 1) A performance or segment of a theatrical production that induces a positive audience reaction strong enough to pause the production.
 * 2) Any impediment that prevents all further progress.
 * 3)  A software bug that must be fixed before any further development is possible.

Usage notes
Ambiguous connotation, depending on context: very good or very bad.

Translations

 * Dutch:
 * Italian: strappa applausi, gran numero, uno schianto, numero eccezionale, esibizione fantastica, applausi a scena aperta


 * French:
 * German: KO-Kriterium, K.O.-Kriterium, ,
 * Italian:, , ,
 * Ukrainian: зава́да