I got the game to break where I wanted it to, but beyond that I don't know what to do. Is there some way I can get the debugger to function as a trace logger and output some code for me to check out? I see there is a tracer option, but it's either not doing what I want it to do or I don't understand it.

Outputs the trace to a file.

I wrote a hack of GEST, but I haven't done as much GB hacking, so I've never really gotten all the bugs worked out.

 Another thing that would be nice to add to BGB (used it recently), is a branch PC history window. Something like the last 20 branch addresses (the address of the instruction itself), for any instruction that effects the PC in a direct manner like; a return, jsr/call, a jump, relative branching (conditional), etc. Like what mednafen has for PCE debugger. That way when you break on something specific, you can work your way backwards through the history window easier and faster to see the higher level code that called/initiated that specific event.