First thought it was a Lifestar medivac helicopter taking off from Saint Vincent Hospital which is nearby.

The witness works at a bayside outdoor bar as a doorman.  He was collecting cover charges from patrons as they entered the bar and appreciating the bayfront skyline, most notably the Port Erie Bicentennial Tower which dominates the skyline view of Dobbins landing which is the name of the district that the bar and tower are situated in.  
He first noticed the object because he believed that it was a Lifestar medivac helicopter taking off from Saint Vincent Hospital which is near the place of the sighting.  It began blinking different colors alternating between red, green and then blue and white at random intervals.  It stopped and hovered in mid air and then began making bizarre right angle turns and wild oscillation in altitude before beginning lazy swoops over the bay and then heading over to Presque Isle across the bay before coming back towards the bar. (out of respect for his employers he will let them remain anonymous) it moved from NE to SW, circled the tower a few times and then began to sweep back and forth over Dobbins landing.  
His immediate reaction was to observe it and conjecture what it could possibly have been.  It was too small and too quiet to be a helicopter, but the range was too far for a civilian drone and the night was too dark to be taking drone photography.  He attempted to point out the craft to a leaving patron; who was unfortunately too intoxicated to take notice of the craft.  The craft then traveled up above State Street proceeding to the S and then ascended above the cloud cover and dissipated into the cloud cover or was obscured by the light pollution of the city.  His immediate reaction was to tell his friends and immediately try and write down everything he had seen in complete detail.  He communicated this via a smartphone to three of his friends.