For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:malkavi/openSUSE_Tumbleweed/home:malkavi.repo
zypper refresh
zypper install stepmania
For openSUSE Slowroll run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:malkavi/openSUSE_Slowroll/home:malkavi.repo
zypper refresh
zypper install stepmania
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:malkavi/15.6/home:malkavi.repo
zypper refresh
zypper install stepmania