In one of my previous projects I used one analog input for multiple buttons using an array of resistors. You prevent a lot wiring going to the Arduino and you save on input ports.
It is possible to design it so you can also detect if multiple buttons are pressed but my buttons is only tested using one button at the time.
Another advantage is that you can easily build the circuit without a PCB. If you do so, be careful with short circuits or isolate, like I did with heat shrink tube.
