[kaoD]

I was also working on a 2048 AI, but you beat me to it! Nice job.

I was at an early stage, my scoring is just the game score (which apparently is flawed!) so nothing fancy. My approach to the large branching factor with the random tiles was just to ignore them and continue the search with a random one until there are less than N tiles free (I empirically found 4/5 to be good), where I perform a full search and apply a simple mean to the resulting scores. Mine is not even minimax, just a simple depth-first search. It wins between 1/4 and 1/5 of the time in a small sample of 200 games, how does yours perform?

This would be a great AI competition! Too bad it takes so long to run lots of games (mine is ~10 turns a second).

I wonder if web workers would speed it up.