Wow, I thought I was masochistic. What possessed you to take DC and GA (two of the hardest classes) together?

I took DC alone and found it manageable if you weren't a perfectionist. Compilers was the most difficult thing I've ever done, though that was mostly due to my own poor time management during phase 3 (generating the intermediate representation). I didn't complete phase 3, so most of my time during phase 4 (emitting MIPS assembly + implementing three register allocation algorithms + optimizations) was catching up.

Also, as a note, the very difficult classes like distributed computing and compilers are completely optional (though well worth it IMO). The only very difficult class that's required is graduate algorithms.

For those not familiar with OMSCS, there are some class ratings here: https://www.omscentral.com/