As R4V3-0N said, player ships are hard coded, which is why this was a total pain in the butt to make.
Possibly, I'm only mildly familiar with regular FTL modding, and I haven't reverse engineered any of the code that deals with that stuff.
My main focus right now is trying to add multiplayer. If someone who knows a lot about modding wants to help me out, that would be awesome. Preferably, someone who's worked on mod tools and actually understands FTL's underlying resource formats (.DAT files, all the XML files, etc).
I'm well aware of those rules, which is why it's distributed as a 300 byte patch file. I'm not distributing a copy of the FTL exe in any form.
As TaxiService said, it's just a patch file, which is used to modify a user's existing FTL exe.
I didn't actually decompile the game.
I've spent the last month or two reverse engineering FTL for the purpose of writing a multiplayer mod. This mostly consisted of running the game in various debuggers, and trawling through a stupid amount of x86 assembler code.
So, I wrote a DLL in C/C++ (with bits of inline assembler where needed) that's injected into the game. The DLL modifies the game's compiled code at runtime.
I'm drawing on the screen by intercepting calls from the game to OpenGL (more specifically, the call that's made when FTL is done drawing the current frame).
I disabled the buttons by disabling bits of code in memory.
The "previous" and "next" buttons work by intercepting mouse clicks and modifying the code that selects a random ship.
The patch file just makes FTL load my DLL so users don't need to use any dodgy injectors.
I seriously think you are a hero. Do you know if your code could be adapted to be used by unix-based operative systems as well?