I designed all the characters in the video with the help of the excellent Smack Studio users, and I animated the blond woman (Roxy) entirely in CTA5. I then rendered her animations to a PNG sequence of 256*256 (to fit the game’s canvas size) and repeated the process to completion.
I even animated the background characters for the first round in CTA5.
The game is called Smack Studio. You can create characters and Stages, and if you want, export the images as a Sprite Sheet for use elsewhere.
Roxy (the blond woman animated in CTA5 and then exported) is a bit jank, but that’s mainly 'cause I was learning as I went.