Major feature list and dev sheet - SonicTHI/SaveOurShip2Experimental GitHub Wiki

This is a list of major changes from the Steam version of SOS2 for RW 1.3:

More details (and spoilers) can be found on the SOS2EXP dev sheet. Ship screenshots (somewhat outdated and spoilery)

Start fresh: the 1.5 release is NOT backwards compatible with prior SOS2 releases! SOS2 can be added to existing games - deconstruct any ship buildings first! You can also start on a ship or space station with the new scenarios that can be further customized in the menus. The 1.4 release is included in the download as well but is outdated and no longer supported.
Rebuilt ship roster: every ship in the mod has been redesigned and built from the ground up utilizing new systems and mechanics making for a more interesting and varied experience. New ships have also been added. Many thanks to the ship wrights that helped with this: HG, Oninnaise, UrbanMonkey, VVither_Skeleton, Rage Nova.
Ship blueprints: sold by weapon merchants. These items allow you to build entire ships and are fully reusable and customizable. You will still need the required technologies and resources to do so (these are listed on each blueprint).
Ground defense: all small ship weapons are now capable of firing on enemy combatants while your ship is landed. Decimate hordes of enemies with the push of a button so long as they are not already too close or your weapons on cooldown. Ship shields will now also block ground projectiles.
Redone heat system: simplified, with less cheese and far better performance. Radiators have been removed while heatsinks now vent heat through the roof even when shielded. Coolant tanks have been added that offer a much larger heat capacity but without the ability to vent it to space. A new vent coolant function is also available from the bridge that sacrifices your maximum capacity for a quick removal of heat.
New shuttle system: SOS2 now requires Vehicle Framework! Shuttles are much easier to use and will have fewer mod conflicts. An upgrade system has been added that lets you customize them to various configurations. Depending on their armaments, shuttles can fly various missions in combat. Set up a fighter screen to intercept torpedoes and boarding parties, or send your bombers to deliver torpedoes past point-defense.
New boarding system and defense: Point-defense no longer just intercepts enemy torpedoes but shuttles as well! Shuttles and pods can now land on enemy bays and will be forced to do so in combat, if room is available. A new map physics option has been added for those who want a more realistic approach to boarding when ships are moving in combat.
New ending and planet travel system: completing the Royalty ending now grants you an imperial destroyer instead of ending the game. Traveling to another planet now ends the game but saves your ship and everything on it to a file that can be loaded by editing a Load ship staring scenario and selecting your saved ship. Revisiting old planets is no longer possible. The ship start scenario has also been updated with similar code to ensure better compatibility and easier maintenance/updates in the future.
New orbit system: Ships now take time to travel from/to orbit and can crash if lacking fuel for a proper landing.
Hologram rework: Biotech's new gene system and other changes caused too many issues with holograms so they have been reworked into formgel swarm like beings.
Random fleet system: face off against randomly generated fleets of ships in various configurations and sizes.
Random wreck system: generates wrecks from ships in the database for you to explore and loot. Other factions and ships might attempt to do the same.
Reworked salvage system: gone are the days of pushing a button and getting a shipload of resources. Use salvage bays to drag defeated ships to your map where you can move and rotate them, split them apart and/or graft parts onto your existing ship. You can also repair or deconstruct them for resources or simply let them burn up in atmosphere. A larger crew or taking advantage of other mods/DLC will come in handy. A new glittertech salvage bay has been added that can scoop up resources from wrecks.
Bridge system overhaul: old large bridges have become obsolete with two new consoles taking on and expanding the functionality. Some functions like scanning have been moved to advanced sensors or the new science console while the tactical variant lets you select various weapon types across your ship provided they are connected to it by the ships heat network.
Docking ports: allow you to temporarily connect ships by using extenders with breathable air, power, heat and chemfuel pipes (if using Rimefeller) up to 3 tiles away and can also connect to each other.
New events and stroyteller: deal with pirates, watch out for debris fields and find abandoned space pods, all with various results and choices. Kim Kismet will less likely fire harmful events on pawns who have been with your colony for years, and more likely to test newcomers in the crucible of the Rim.
Gremlin xenotype: Gremlins are engineered starship crew, able to endure vacuum exposure and secrete a cryptosleep cocoon.
Performance optimizations: from faster EVA checks to a completely rebuilt ship caching and combat system - a lot has been done to improve the performance of this mod.
New UI and settings menu: the ship battle UI has been moved bellow the pawn bar. It now shows all ships and can be moved or made persistent in the SOS2 settings menu. SOS2 settings have been reset to their defaults as we now use the native RW mod tools. Hugslib has been removed as a required mod.
Tons of other minor adjustments, balance changes and bugfixes.
Extendability: it is now easier to mod in new types of ship buildings, shuttles or add EVA functionality to other mods. A navy system has also been added so modders can add factions with their own pawns, ships and colors.
Creation kit: now includes new tools for fleet and blueprint creation as well as improvements to existing ones.