This is a play example of Fantasyflight's boardgame : Descent, second edition.
It is the first encounter of the Quest "Death on Wings" (turn 1)
I made the MAJOR ERROR of playing it the wrong way : my heroes enter the exit and go towards the entry, which makes things extremely tough.
I will, if time and energy are granted, redo the whole thing correctly some day and post it here.
I TIMED at 12 seconds the time slides are shown : if too fast, just use the PAUSE/PLAY buttons.
The (bad) music track is 1st movement of Mahler's 6th Symphony.