If there is no uninstall option you need to manually remove the files.
Most (if not all) of the files will be installed inside a directory (from the readme I would assume it is called
ns-allinone-2.35) at the path you ran ./install. Simply use a
rm -rf to remove that directory and it will be gone.
Now for 1 extra step: during installion either the installer added some links to
~./bashrc or you edited them in yourself. So do a (backup at the 2nd command):
cp .bashrc .bashrc_old
and have a look for anything related to
ns-allinone-2.35 and remove it. Be careful; if you mess up it might be problematic. After editing you need to parse the changes: