Scratch

"Hello there, organism #4829822. The world is currently undergoing a total and complete apocalypse. Stay out of trouble, OK?"

Extinction is your typical retro styled survive-for-as-long-as-you-can game - with a twist.
Every 5 seconds, something extra happens. The game might speed up permanently, the fireballs might start moving faster - hey, you might get 2 free points! Only those who can adapt to the rapidly changing gameplay will survive. Can you?

And, without further ado, here is the link:

http://scratch.mit.edu/projects/Akorlith/2802306

You MUST use flash. The Java player does NOT work with this. Alternatively, you can download it and play it in Scratch. Either works, I guess.