Well, where to start? So many changes...

The main files where space is located is in space.c, ships.c, and 11.c.
Code-generated ship building/buying is in ships.c
Two pilot maneuvers are in 11.c, the rest (generally) is in space.c

Alright, so, primary and secondary weapon systems. Instead of lasers or 
ions, there is now primaryType, secondaryType, primary/secondaryCount, 
etc. Many different beam weapons, such as lasers, duallasers, 
triplelasers, quadlasers, autoblasters, heavy lasers, light ions, heavy 
ions, repeating ions...

Ship-to-ship hit calculations now based on speed, maneuver, and most 
importantly, ship size.

There's a 'black market' shipyard, made by typing 'redit flags2 
blackmarket'. On boot/copyover, it generates a new list of ships. Ships 
available are only clanned ships. You can buy from, and also sell to, the 
black market.

Capability to link-fire primary, secondary, and warhead weapon systems.

Ship simulators, which allow for risk-free space combat, can be made. You 
must 'setship <ship> flags simulator' and 'setship <ship> simvnum <room 
vnum to return to when destroyed/endsimmed>'. Not doing the former will 
cause the ship to blow, not doing the latter will cause crashes.

Two maneuvers, barrel roll and juke. Barrel roll evades beam attacks for a 
time, juke evades warheads for a time. After a set amount of time, or when 
the command is interrupted, flight pattern 'levels out' and becomes as 
vulnerable as it was before.

Likely much more...probably best just to skim through the files.

-||

Addendum: Upon some servers with limited file space there may be some
troubles with corrupt pfiles or a corrupt shipvnum.are. Provided is a
shipvnum.are.CLEAN, so if your shipvnum.are becomes corrupt, just replace
it with this one and clear out the space file of any bought ships. (This
is also how to do a shipwipe). Also recommended if you have limited file
space is to make pfile cleanup delete players quicker.