Hi Wedrownik, you can have animations with different duration played at the same time
Just ask your programmer to set the animations to be played on different track index:
state.setAnimation(0, "clouds", true); // use track 0
state.setAnimation(1, "windmill", true); // use track 1
state.setAnimation(2, "campfire", true); // use track 2
Those animations will be played simultaneously on different tracks.
I just did so with my world map some days ago.
The only issue with multi duration animations is that it is not easy to preview all animations together in Spine Editor.
I hope there is a shortcut in Spine for this kind of preview. e.g. something like selecting multiple animations then auto play them on different tracks on the preview panel.