$ sudo dpkg --install zsnes_1.510-0ubuntu1_i386.deb
dpkg - warning: downgrading zsnes from 1.510-2.1ubuntu1 to 1.510-0ubuntu1.
(Reading database ... 192706 files and directories currently installed.)
Preparing to replace zsnes 1.510-2.1ubuntu1 (using zsnes_1.510-0ubuntu1_i386.deb) ...
Unpacking replacement zsnes ...
Setting up zsnes (1.510-0ubuntu1) ...
Processing triggers for man-db ...
Processing triggers for menu ...
Processing triggers for doc-base ...
Processing 1 removed doc-base file(s)...
Registering documents with scrollkeeper...
Can confirm that http:// launchpadlibrar ian.net/ 18798999/ zsnes_1. 510-0ubuntu1_ i386.deb works perfectly fine, however, it is considered a "downgrade".
$ sudo dpkg --install zsnes_1. 510-0ubuntu1_ i386.deb 510-0ubuntu1_ i386.deb) ...
dpkg - warning: downgrading zsnes from 1.510-2.1ubuntu1 to 1.510-0ubuntu1.
(Reading database ... 192706 files and directories currently installed.)
Preparing to replace zsnes 1.510-2.1ubuntu1 (using zsnes_1.
Unpacking replacement zsnes ...
Setting up zsnes (1.510-0ubuntu1) ...
Processing triggers for man-db ...
Processing triggers for menu ...
Processing triggers for doc-base ...
Processing 1 removed doc-base file(s)...
Registering documents with scrollkeeper...