I was made aware of this theme in a Reddit thread (which I can no longer find) however upon installing it I noticed that the text in the listing of games under a console was misaligned.

Misaligned Text in snes-mini Theme

Thankfully a quick Google search turned up this issue on GitHub. One commenter was able to resolve the issue by editing one of the layout files. Applying the fix and restarting EmulationStation on my RetroPie did the trick and now text is properly aligned! If you're using a 1920x1080 resolution (which is default) you can replace the contents of the /etc/emulationstation/themes/snes-mini/layouts/1920x1080.xml with the following to fix the misaligning text issue:

author: ruckage

    <view name="basic,detailed,video">
        <textlist name="gamelist">
            <pos>${listx} 0.19537037037037</pos>
            <size>${listWidth} 0.62962962962963</size>

If you're not using 1920x1080, you can head on over to this PR on GitHub to see the fixes for other resolutions.

This is definitely one of the better themes I've seen for EmulationStation, the rest look pretty awful in my opinion.

Fixed snes-mini Theme