Sure! In a nutshell, just install it using sudo apt-get install scummvm
The problem is, scumVM requires you to use an F5 key to access the menu to quit. There’s no way to remap this within the app, so you’ll be stuck trying to return to the launcher without restarting.
You’ll need to either need to use xmodmap (it’s already installed on stock 0.5 AFAIK) to change the mapping of an existing key to F5 (oh wow why didn’t I think of that before? I might just do that!) or do what I initially did, and install xbindkeys (sudo apt-get install xbindkeys) or something similar to invoke a kill switch to terminate scummVM, return your binding to normal and terminate xbindkeys.
I made a file ~/.bindscummvm containing:
"killall scummvm && xbindkeys --defaults > ~/.xbindkeysrc && killall xbindkeys"
l + h + o + y
Looking back, I was lazy. I might actually make an xmodmap instead, in addition to the xbindkeys. From here, just make a scummvm.sh menu entry (and an icon if you wish) where you want (writing the executable bit {chmod +x}) referencing the above changes on launch. Since it’s installed properly to the usr space, you can invoke it using the command scummvm
Here are my scummvm.sh file contents:
#!/bin/bash
xbindkeys -f ~/.bindscummvm
scummvm --joystick
I also included the parameter --joystick in case people haven’t flashed the mouse firmware to their arduino keyboard. However since the keyboard is essentially well, a keyboard and not a joystick I’m not sure if it actually does anything.
Oh that’s another thing. Flash the mouse custom firmware to the arduino keyboard. 
Currently I have it set to SHIFT+ABXY (LHOY) mash as the exit key combo. Not exactly eloquent, but better than holding the power button!
I was actually thinking of using this key combo as a universal kill switch for whatever app is currently in the foreground, ie kinda like the old game boy AB+start+select soft reset key combo.
Now. I’m not sure if you’ll need to install any extra dependencies for running midi on a stock firmware. I just know that I installed a bunch of things to get midi working while installing Zdoom. Ooh good thing you brought this to my attention. I’ve only tested ScummVM on my own day to day image with zdoom installed. The one currently up for download doesn’t have it, since it didn’t receive many votes when I put up a poll.
It might be easier if you just install Zdoom along with its dependencies if sound isn’t working in ScummVM.
Check out this script
Probably just pick and choose between these:
sudo apt-get -y install g++ make cmake libsdl2-dev git zlib1g-dev libbz2-dev libjpeg-dev libfluidsynth-dev libgme-dev libopenal-dev libmpg123-dev libsndfile1-dev libwildmidi-dev libgtk-3-dev timidity nasm tar chrpath patchelf
From here, you shouldn’t need go touch any of the sound settings in ScummVM. You may want to adjust the graphics mode to “Normal (no scaling)” to make the menu readable from the Gameshell screen.
Of course, all this will be way easier if you just downloaded my community image, but I can understand not wanting to start from scratch. Man I should really just find a way to have a patch to upgrade an existing 0.5 installation to incrementally include whatever things people want. The dream. That seems to be the biggest grip against people using this community image.