[Jach]

Blunders are fairly easy to notice in-game or afterward in review, but yeah it can be frustrating when you don't feel like you made a big mistake but still lost by a lot. If you have a better player look it over though they'll at least find a bad / inefficient move pretty much every few moves that "only" loses you maybe 3-5 points but the accumulation at the end is pretty big. Personally I like GnuGo for doing some post-game move analyses (I use the GoGui client) but I think I'd fare much better having a good player review or do a teaching game... Still, it's kind of fun to look at its suggested Top Moves, or try letting it finish a game (Final Score -- I think its Estimate Score is pretty terrible, though AlphaGo's would be nice to have on hand...) with itself after certain points to see if any are decisive for it. Another fun thing I did recently with a wild full game was have GnuGo annotate every move with the top moves it would have picked along with marking dead or critical groups. (The command is: `gnugo --level 15 --output-flags dv --replay both -l input-game.sgf -o annotated-output-game.sgf`)

What I really want is a kibitzing clock when playing other people: http://www.emptytriangle.com/archive/show/8