Hey this is my favorite game from the entries that I've played. It looks like you used spine - did you buy the full version?
Hello my friend, thank you so much. Spine is an amazing software (I'll try later, but the free version is very limited to test stuff), so I'm using spriter2d: https://brashmonkey.com/
Both are bone animation based.
It is easy to use it with libgdx, you only need to export your animation as a .png spritesheet (horizontal or/and vertical frames) and create an Animation with all frames, so in code just do a TextureRegion.split and fill the Animation with all frames, you can see my code here (line 176-186): Code
Hope it helps! ;D