I’m guessing you didn’t get to the point of actually breaking the tiles. 🙂
In fact, my game is quite similar to yours in its theme. The black spots are actually slowly forming cracks in the tiles on the floor, not dust. If a tile gets too cracked, it breaks completely, leaving a black hole where your movement is slowed down tremendously. Holding the space bar to rush in this game represents pushing yourself to work excessively hard, and broken tiles represent burnout as a result of that. The overall effect of this is to create a downward spiral as you try to keep up with your workload (represented by catching the falling hammers), but the level of workload requires you to push yourself to an unsustainable degree. As holes accumulate, it gets harder and harder to get around the room until eventually, the burnout is too much and you fail to catch one of the hammers in time.