For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:oberkut/openSUSE_Tumbleweed/home:oberkut.repo
zypper refresh
zypper install widelands
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:oberkut/15.6/home:oberkut.repo
zypper refresh
zypper install widelands
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:oberkut/15.5/home:oberkut.repo
zypper refresh
zypper install widelands
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:oberkut/15.4/home:oberkut.repo
zypper refresh
zypper install widelands