The first gaming console that my wife and I owned was a Sega Genesis, and I still enjoy playing old Sega games from the golden era of the early 1990s. There are 2 emulators available for Ubuntu and Mint that will play Genesis games. In both cases, you will have to uncompress whatever ROM you plan to run (they are nearly always zipped).
DGen – DGen is actually a pretty good emulator, but it has one drawback: it needs a graphical front end. There is one, but it’s old and requires you to have the Tk language installed (easily obtainable from the Ubuntu repositories, and not a very large size). You can get it here. After downloading, unzip the file and create it from the source code. This is easy…just cd (change directory) into the tkdgen-1.1.1 directory and issue the following commands: “./configure”, “make”, and “sudo make install” (which will ask for your password). Once it’s set up, you can run it from a terminal by simply typing “tkdgen” and pressing ENTER (you won’t need to be in the tkdgen directory, just in your home directory).
DGen offers 4 resolutions plus full screen, and configures your joystick automatically if you have one connected and Activated. I find the 3x resolution to be the best. Sound doesn’t get slowed or distorted no matter what setting you use for the resolution. (Activate joysticks thru the DGen > Joystick menu).
Gens – Gens is a very nice emulator for Sega Genesis games, but it doesn’t run the Sega Master System games. This is a good choice to play Genesis games, but is superseded by the most recent fork below.
Gens-GS – This is definitely the emulator you’d want to use. It’s a fork of Gens, with the code cleaned up and currently maintained. Both this and the original Gens are not in the regular repositories; you’ll have to enable the additional getdeb gaming repository. There are several settings for resolution, but just like the GFCEU emulator for Nintendo, some of them smooth or soften the graphics in a way you may not like. If you use too high a resolution, I find the sound to be somewhat lower in quality as well. For this emulator, I prefer using the “Double” resolution, with no further adjustment. It keeps the exact appearance of the games.
Using this full-screen works fine, but you need to start a game up before switching to fullscreen mode. Use ALT+ENTER to return to a windowed version.
Yabause – This is a Sega Saturn emulator. Unlike older consoles, you need additional components, such as the correct BIOS, in order to play Saturn games. I don’t really bother with trying to get those games running. But it does feature a nice front end, and you can adjust the window size.
For further information about Yabause, check out their official site.