Experimental SuperTux nightly builds for Linux are available via FlatPak:
sudo flatpak remote-add --no-gpg-verify supertux "https://gitlab.com/supertux/flatpak/-/jobs/artifacts/master/raw/supertux-repo?job=build:flatpak"
sudo flatpak install supertux org.supertuxproject.SuperTux
flatpak run org.supertuxproject.SuperTux