Install openRA with snap

sudo snap install openra

Install original videos for C&C
https://github.com/OpenRA/OpenRA/wiki/Game-Content
https://cncnz.com/features/freeware-classic-command-conquer-games/

sudo snap connect openra:removable-media

sudo apt install unrar

sudo mkdir /media/openra

# C&C
wget https://files.cncnz.com/cc1_tiberian_dawn/full_game/GDI95.zip -q -P /tmp
wget https://files.cncnz.com/cc1_tiberian_dawn/full_game/NOD95.zip -q -P /tmp
wget https://files.cncnz.com/cc1_tiberian_dawn/full_game/CovertOps_ISO.zip -q -P /tmp

unzip /tmp/GDI95.zip -d /tmp/
unzip /tmp/NOD95.zip -d /tmp/
unzip /tmp/CovertOps_ISO.zip -d /tmp/

sudo mount /tmp/GDI95.iso /media/openra

openra.cnc

# Manage Content > Detect Disc or Installation > Select content > Continue

sudo umount /media/openra
sudo mount /tmp/NOD95.iso /media/openra

# Detect Disc or Installation > Select content > Continue

sudo umount /media/openra
sudo mount /tmp/covert.iso /media/openra

# Detect Disc or Installation > Select content > Continue

sudo umount /media/openra

Install original videos for RedAlert

wget https://files.cncnz.com/red_alert/full_game/RedAlert1_AlliedDisc.rar -qP /tmp/
wget https://files.cncnz.com/red_alert/full_game/RedAlert1_SovietDisc.rar -qP /tmp/

unrar x /tmp/RedAlert1_AlliedDisc.rar /tmp/
unrar x /tmp/RedAlert1_SovietDisc.rar /tmp/

sudo mount  /tmp/RedAlert1_AlliedDisc/RedAlert1_AlliedDisc/CD1_ALLIED_DISC.ISO /media/openra

opnera.ra
Manage Content > Detect Disc or Installation

sudo umount /media/openra
sudo mount  /tmp/RedAlert1_SovietDisc/RedAlert1_SovietDisc/CD2_SOVIET_DISC.ISO /media/openra

Retry

sudo umount /media/openra

rm -r /media/openra
rm -r /tmp/RedAlert1_*

Check for latest version
https://snapcraft.io/openra