Using window washing as a gameplay hook was pretty interesting and I loved the way the "story" progressed. I really didn't expect a plot twist in a window washing horror game but here we are.
I would say though, the mechanic got a little stale. It's a short game, but the number of times I had to look away from the window to grab a tool could be reduced. Maybe LMB could be scrub and RMB could be spray? It would keep players looking at the window longer.