Can you tell what the airplane is doing?

The odd one out

The turn coordinator's left wing is low, the attitude indicator is banked left, the heading indicator is turning left, and the ground lights out the window agree: it's a left turn. The altimeter is unwinding and the attitude indicator shows the nose low, so the airplane is descending. The VSI is the only instrument showing a climb. When one instrument disagrees with the rest, that's the one to suspect.

The hint

Listen to the very end. ATC tells the airplane to expedite its descent to 3,000, so the controller is confirming a descent on radar.

Why not a static blockage

A blocked static port is the classic pitot-static failure, but it freezes the altimeter, and this altimeter is unwinding. A working altimeter means a working static system, so the VSI failed on its own. VSI lag doesn't explain it either. Lag delays the needle for a few seconds; it doesn't point it the wrong way for the whole descent.

The airspeed is fine

The power is set to low RPM, so the airplane can come down at about the same airspeed. Less power means you descend instead of speeding up.