Flash is completely deprecated, so I am not able to run the game. Also, Kizi's HTML 5 version of the game is completely different from the original Red Ball 5.

Well. You can get the game in the recourses on speedrun.com. The standalone version still works because it wasn't running on the website.

@KrishnaDas As @MarioMario7829 said, you have to use the standalone download version. It can be found inside the Definitive Collection files here: https://www.speedrun.com/redball1/resources .