Indie game storeFree gamesFun gamesHorror games
Game developmentAssetsComics

It's just tweening image_xscale and image_yscale.

I recently found out about TweenGMS PRO. Is that what you use or is it just custom?

I didn't make this game btw.

Tweening is easy to implement custom. What's more important is how to use tweening.

I recommend watching this, if you haven't already: