On the game page they cite using the shmup creator engine.
Only thing I find searching for shmup creator is this, which is a drag-and-drop engine for creating shmups: https://store.steampowered.com/app/1289520/SHMUP_Creator/
On the game page they cite using the shmup creator engine.
Only thing I find searching for shmup creator is this, which is a drag-and-drop engine for creating shmups: https://store.steampowered.com/app/1289520/SHMUP_Creator/
On further inspection none of my extensions are working, please disregard what I said before. I probably just imported them wrong. With this one and a couple of the others it also said “Error parsing JSON file: unexpected end of input” which lead to me opening the .aseprite-extension files with winrar and manually installing them.