Are you allowed to drive onto the level crossing when the barriers are not fully lifted?

In the video you are standing before a level crossing: a train has passed, and the barriers are going up but have not yet reached the vertical position. When the barriers are not fully raised, entering the crossing is prohibited. The answer is: no.

The Road Traffic Act prohibits driving around lowered barriers or half-barriers and entering a crossing if they have started to go down or have not finished going up. A barrier halfway up may stop, go back down or hit the roof of the car, and its movement does not yet mean that the tracks are clear. You move off only when the barriers are vertical, and before entering the tracks you check yourself that nothing is coming.

Legal basis: Art. 28 para. 3 point 1 of the Road Traffic Act (Prawo o ruchu drogowym)