Possibly one of the earliest flash games that I could remember playing, was a game called Squares 2 that is playable on albinoblacksheep.com.
Squares 2 is simply a collect-em-up in the same vein as Kaboom on the Atari 2600, except you’re using a mouse and you’re moving in all directions rather than right and left.
You simply move a rotating black square around on the screen as black and red squares move across the square. The idea is that you collect black squares and avoid the red squares.
Touching any red square will give you a Game Over.
There are circles that appear in the game too. There are black and red circles. Collecting black circles give you point bonuses or advantages such as slow down or make your cursor square smaller. Collecting a red circle will make your square bigger, making it harder to avoid the red squares.
So if you’re interested in this game, you can play this version free on the Albinoblack Sheep site. However there is an Android version of this game too, but the awesome Daft Punk music isn’t on it though.