I finally got around to playing this after having it on my computer for about a month. I just want to say this scenario is phenominal. I haven't had this much fun with a scenario since El Justo's Cold War. What I most like about this is that the gameplay is pretty straightforward, and doesn't deviate too much from the original Civ game mechanics; the nonlinear tech-tree was a nice touch also (even if it takes some getting used to

).
The only suggestion I would make is that each faction have one unique unit like in a normal game of Civ. I took the liberty of adding them to my own personal copy of Space Opera. Here are the ones I came up with if you want to take this idea into consideration (the Space Guild's and Shadow Cartel's come from their Pedia entries):
Solar Empire: Imperial Stormtrooper- Has superior offesive capabilities. Replaces Marine. Suggested graphic:
Chukchi Husky's Conscript
Divine Council: Missionary Infantry- Can convert enemy units but has diminished combat ability. Replaces Grunt. Suggested graphic:
LizardmenRule!'s Modern Inquisitor
Synthetic Union: Core Defender- A massive combat droid designed for the defense of the homeworld, but can engage in limited offensive operations as well. Ane extra defense unit made available with Special Forces advance. Suggested graphic:
muffins's Zenith Mecha
Space Guild: Navigator Initiate- Can airdrop and carry out recon missions. Replaces Ranger (had to take away the normal Marine units' airdrop ability to get this to have the effect I wanted). Suggested graphic:
muffins's Technoangel
Confederacy: Hammerhead-Class Destroyer- Fastest warship in the galaxy, sacrificing transport capacity for more powerful engines. Replaces Destroyer. Suggested graphic:
muffins's Executioner
Ragers: Reaver- Can attack more than once, has almost no defensive ability. Replaces Soldier. Suggested graphic:
la dav's Super Soldier
United Republic: Minuteman- Citizen-soldier who can do worker jobs, but can also be called on to fight in desperate times. Replaces Worker. Suggested graphic:
Smoking mirror's Autogun Armed Imperial Colonist
People's Alliance: Combat Police- Excellent defenders, almost useless in offesives. Replaces Guard. Suggested graphic:
Smoking mirror's Uniformed Imperial Trooper
Brotherhood of Orion: Sacred Band- Amphibious, equally effective on offense and defense. Replaces Grunt. Suggested graphic:
Kinboat's Angel
Shadow Cartel: Deadly Viper- Assassin that is invisible and can stealth attack. Replaces Operative. Suggested graphic:
embryodead's Witch Elf
The Swarm: Swarmling- A bit weaker but can be produced in overwhelming numbers. Suggested graphic:
CivArmy s. 1994's Alien
Weyland Corporation: Blade Interceptor- Starfighter with superior range and firepower. Replaces Starfighter. Suggested graphic:
Olorin0222's V-19 Torrent
Sorry if you don't want this, but I just can't help myself when it comes to tinkering with scenarios.