C Executable Reverse Engineering Needed

I have several Windows executables and accompanying .dll files that were originally written in C, but the source code has been lost. I will supply only those compiled binaries; no partial code or documentation is available. Your task is to work through the binaries, reconstruct human-readable, buildable C source, and document any non-obvious logic you uncover along the way.

I expect the recovered code to compile on a current GCC/Clang toolchain, reproduce the original behaviour, and be organised into clear modules with meaningful comments. Feel free to use IDA Pro, Ghidra, Hopper, Radare2, or any other reversing tools you are comfortable with—just note your workflow so I can maintain the codebase afterward.

Deliverables
• Complete C source tree that builds cleanly (no warnings with ‑Wall if reasonably possible)
• Brief technical report outlining the binary analysis process, major functions located, and any unresolved sections

If you discover obfuscation or security mechanisms that prevent a faithful recovery, flag them early so we can decide whether to stub or fully emulate that functionality.

I’ll be available for quick turn-round questions and test cases as you progress.