Film: Kill 'em All

Seven of the deadliest assassins in the world are kidnapped in a single day. When they wake up, they're in a bare concrete basement somewhere, and a voice on a loudspeaker informs them that they'll be fighting each other, one on one, until only one is left alive.

Kill 'Em All is a 2012 low-budget martial-arts movie starring Gordon Liu, Tim Man, and Zom Ammara (a.k.a. Ammara Siripong).