Today the official release of Beta 2 for Sins of a Solar Empire: Rebellion will be made available on via the Steam client. This update contains a large number of bug fixes and balance changes, but most notably the addition of the Loyalist and Rebel Advent factions. 

Here's the list of changes from 0.62 (Beta 1a):

[ Graphics ]

• Added intro video!
• New Rebellion research subject buttons now have a white glow.
• Added new particle mesh shader.
• Removed the gravity well texture and replaced it with a player-color circle.
• Added custom Artifact planet for the Occupation Victory condition.
• Updated Advent Iconus Guardian Shield Projection ability particle.
• Updated Advent SpiritBlade weapon particles.
• Added new button icons for updated corvette passive abilities.
• Fixed some mesh and texture bugs with the TEC Rebel titan.
• Fixed glowing missile turrets deployed from the TEC Sova Capital Ship.

[ Gameplay ]

• Advent Loyalist and Rebel Factions added!
• TEC Loyalists
• Loyalist Titan Balance Changes:
• HP per level reduced to 504 from 1040.
• Shields per level reduced to 567 from 750.
• HP restore rate increased to 3.7 from 3.1.
• HP restore rate per level reduced to 0.65 from 0.7.
• Shield point restore rate increased to 5.5 from 4.5.
• Shield point restore rate per level increased to 1.0 from 0.7.
• Armor per level reduced to 0.875 from 0.918.
• Flak Cannon damage reduced to 30 from 75; cooldown increased from 5.5 to 7.0; range reduced from 5500 to 4500.
• Changed Group Shield ability to autocast only in combat.
• Disruption Matrix ability cooldown changed to 45/45/45/45 from 60/55/50/45.
• Disruption Matrix ability damage reduced to 40/50/60/70 from 50/60/70/80.
• Loyalist Corvette Changes:
• HP changed to 350.
• Shields changed to 130.
• Armor changed to 1.0
• Mass reduced to 500.
• Movement updated.
• Weapon DPS adjusted.
• Passive changed to Disable Engines - Chance per hit of inflicting enemy ship with a 25% penalty to Linear Speed and Turn Rates for 45 seconds; can stack 5 times.
• TEC Rebels
• Rebel Titan Balance Changes:
• HP per level reduced from 650 to 441.
• Shields per level increased from 425 to 477.75.
• HP restore rate decreased from 3.7 to 3.1.
• HP restore rate per level increased from 0.45 to 0.7.
• Shield point restore rate reduced from 5.0 to 4.5.
• Shield point restore rate per level increased from 0.6 to 0.7.
• Armor per level reduced from 0.8 to 0.595.
• Flak Cannon damage reduced to 30 from 75; cooldown increased from 5.5 to 7.0; range reduced from 5500 to 4500.
• Scattershot Overcharge damage changed from 250/500/750/1000 to 375/750/1125/1500, duration reduced from 60 to 45, damage changed to Physical.
• Snipe Overcharge damage increased to 3000/4500/6000/7500.
• Added missing finish condition to Overcharged Snipe ability.
• Explosive Shot ability range increased to 10000 from 8500; AoE radius increased to 5000 from 3500; Damage reduced to 600/1000/1300/1600 from 1200/1400/1600/1800; impulse reduced.
• Overcharge ability cost reduced to 40/30 antimatter from 120/100; cooldown reduced to 60/40 from 140/120.
• Fixed bug that prevented TEC Rebel players from colonizing the Occupation Victory planet. The Occupation Planet player is now its own entity, so TEC Rebels will need to conquer it the hard way.
• Changed Pirate Mercenaries to no longer auto-summon pirate ships. Pirate forces can now be spawned from an ability added to the Broadcast Center.
• Rebel Corvette Changes:
• HP changed to 350.
• Shields changed to 130.
• Armor changed to 1.0
• Mass reduced to 500.
• Movement updated.
• Weapon DPS adjusted.
• Passive changed to Cripple Defenses - Chance per hit of inflicting enemy ship with 5% increased Physical weapon damage for 45 seconds; can stack 10 times.
• TEC
• Corsev's Elite Crews ability updated: Shield Restore bonus increased from 33%/66% to 70%/100%, added Linear Thrust bonus to match Linear Speed bonus, increased Duration from 90/120 to 180/240.
• Corsev's Boarded Demo Teams ability damage increased from 400/600/800/1000 to 600/866/1133/1400.
• Corsev's Salvage Teams healing increased from 1%/2%/3%/4% to 10%/15%/20%/25%.
• Corsev's Boarded Salvage Teams healing increased from 5%/10%/15%/20% to 20%/25%/30%/35%.
• Corsev's Salvage Teams range increased from 3000/3500/4000/4500 to 4000/4500/5000/5500.
• Titan build cost reduced to: 9500 credits, 1200 metal and 750 crystal.
• Titan maxRollRate decreased from 1.5 to 0.65.
• Rebuilt Titans will now retain their former incarnation's XP and level, instead of just level.
• Fixed bug that prevented players from joining out-of-game Steam invites for multiplayer.
• Fixed the bug that prevented ships from attacking.
• The Artifact planet/star will now only appear if the Occupation Victory condition is enabled.
• AI should no longer put bounty on players who have researched Truce Amongst Rogues.
• Fixed bug that caused massive slowdowns while playing.
• Kill ship missions will now include Titans as valid targets.
• AI should now attempt to stop another player from winning via Research Victory.
• Fixed bug that would allow harder AI players to instantly win a Research Victory.
• The Pirate planet and Artifact planet now have enhanced defenses.
• Adjusted Solar Storm passive on blue stars to now give a 50% penalty to hull/shield passive regeneration instead of disabling them completely.
• Fixed bug with DestabilizationProtection target filters that was increasing the HP/AM penalty from Starbases.
• Updated retreat logic for AI.

[ Interface ]

• Fixed the order that ships appear in the Empire Tree to: Flagship > Titan > Capital Ship > Everything Else.
• Added HUD/LOD icons for the Artifact planet (Occupation Victory).
• Added custom Advent UI.
• Shifted down the Victory Tree area when playing back a recorded game to prevent overlapping.
• Added Loyalist / Rebel text to player InfoCards in the Relationship window.
• Fixed some interface texture bugs.
• Disabled clickable buttons on mission creation screen that didn't actually do anything.
• Fixed incorrect picture for TEC Flagship.
• Fixed a bug that prevented the autocast animation from appearing on Titans with auto-upgrade enabled.
• Updated selection system to switch to a bounding box check if the main view icon for the entity would be visible to the current camera.
• Added LCD support for Logitech G-Series keyboards.

[ Audio ]

• Added new game event voice-overs.
• Added new victory game event voice-overs.
• Added Rebel corvette voice-overs.
• Added voice-over for no Titan Factory found.

[ Modding ]

• Added new modifier: AntimatterRestoration.
• Added new modifier: ShieldPointRestoration.
• Added new modifier: HullPointRestoration.
• ConvertData.exe now available.
• Updated GalaxyForge now available (check install directory).

[ Misc. ]

• Lots of string fixes and corrections.
• Achievements should now properly work.
• Updated Credits text file.
• Fixed several null pointer crashes.
• Fixed a connection crash bug related to titan construction.
• Fixed exploit that would let players avoid capital crew limits.
• Added Titan Stats to the end-game display.
• Stats files now have the "reb" suffix.
• Save games, screenshots, settings and other Sins files have been relocated to: My Documents\My Games\Ironclad Games\Sins of a Solar Empire Rebellion.
• Steam Cloud saves/loads are now enabled.