This game was originally released on Scratch and received updates before it was released here. There's an update log here though:

1.0.0: Release
1.1.0: Added code that would make the velocity variable go to a positive when you go left instead of a negative, also added a glow in Volcanic Eruption
1.2.0: Added two new playable characters: Z-101 and Z-102. They play exactly the same as Tommy
1.3.0: Added two new MORE playable characters: Z-104 and Z-105. They also play exactly the same as Tommy
1.4.0: Added @Luke51632 on Scratch as a playable character. And can you guess what he plays like? Go on, guess. I bet you don't know the answer.

He plays exactly the same as Tommy.
1.4.1: Added a little "mission" thingy to the title cards.

Announcements:

A sequel is planned. That is all.