Fun game, but the "ace => one shot" from the description doesn't work, at least I interpreted that as "ace kills in one shot" which doesn't work.
Also, because you can shoot so quickly and bullets do so little damage, there is not much reason to play "tactically". I just spam shoot bullets at enemies. Maybe if individual cards dealed more damage, and you shot way slower, and the joker healed more, there would be an actual good reason to play tactically and watch what you're shooting.