Use Flashpoint 13 Infinity to play them.
Flashpoint download:
https://flashpointarchive.org/downloads
Here's the list of flash games I played.
& recommend:
McDonald's Video Game (by Molleindustria)
Snowfight 3D (by Fetchfido)
Pandemic II
Raft Wars
Raft Wars 2
Interactive Buddy
Age of War
Age of War 2
Spider-Man: City Raid
The Last Stand
The Last Stand 2
Stick RPG
Warlords: Call to Arms
Warlords 2: Rise of the Demons
Warlords: Heroes
Territory War
Bowman
Bowman 2
Dino Run
Learn to Fly
Boxhead 2Play
Boxhead MoreRooms
Bloons
More Bloons
Even More Bloons
Bloons TD
Bloons TD 2
Swords and Sandals
Swords and Sandals 2
Line Rider
Feudalism series
Thing Thing 2
Thing Thing 3
Thing Thing 4
Thing Thing Arena 2
N: The Way of the Ninja
QWOP
Super Mario 63
The World's Hardest Game