We actually discussed this! But ultimately we went with "Die" because of the "die and retry" nature of roguelites and roguelikes :)
Nice, I also like "A Good Day To Die" a lot, so i can see why you guys chose this one. Very cool game.
A singular of dice is die, so it works as both a pun and good wordplay in general. a good day to dice might make ppl think it's an entirely different game.