decent idea, i was expecting a mastermind type game as opposed to a high/low guessing game. still alright, I agree about the number pad comment, plus "enter" while it can start a level, connot be used to go to next level.
I like the game. You need to fix high scores. It could use more levels, possibly a different level progression. I think maybe the timer should start and stop at the beginning and end of the goal accomplishment to avoid the delayed fire signal affecting the players time. 4 of 5 for originality.