Pause ahead looks like something I would greatly enjoy back in the day, I kinda want to give it a try.
I don't know which flash games are considered niche, since I haven't seen anyone talk about them in years, even if a lot of games had really cool ideas. But I distinctly remember two, though, and with my bad memory that must mean something xD
One is a series of point and click games called Submachine. It had cool vibes, plot, mystery and mechanics.
The other I can think of is Samorost, that I believe was made into its own series later? Very cool surreal art style.