Multiplayer.
I really like this game, but I feel a little lonely and sometimes can't make the weapon in time, if there will be a multiplayer, I got a few suggestion:
PVP: player have to make the weapon that the system want in time, if one of the player lost a customer, then he/she is the loser.
PVE: players have to work together.
I would really want to see multiplayer will be added into the game! :D love your game bro.