This isn't TI|BD's [tibd]Mastermind[/tibd] game!
I made a version of Mastermind in 439 bytes (including the name, MSTRMIND). It uses numbers 0-9, keypresses instead of Input for inputting numbers, and it shows red and white pegs instead of right/part-right/wrong numbers.
I got the white peg formula from
Wolfram Mathworld. This is it, as used in the program:
c
i is how many times color i was in the code, and g
i is how many times it was in the guess. r, of course, is how many red pegs thrown out.
The file is attached. You press the number pad to input numbers, ENTER to guess it, and CLEAR anytime to quit. A half-second after guessing, you will see the change in red and white pegs. You get 14 guesses.
Give tips for even more optimization, if possible!