We used Affinity Designer for the foreground tileset, including the Jam and plate sprites.
The background was initially generated using bings generative AI and then modified to fit our style in photoshop.
The character was inspired by a generative AI image too, but broken up into the component parts in Krita and animated in Godot. In hind-sight I'd like to have done the character in Affinity Designer too, as setting up the layers in Krita was pretty awkward.
All the UI is just using features in Godot and a font downloaded from frontspace.com.
Hope this helps!