Hi,
currently the launcher uses a busy-loop in it's main-loop. This really eats up battery.
Why not use alarms? Set up an alarm for each button and then send the device to light sleep. Deep sleep should also be possible, but is a little bit more involved. I have this on my own todo-list but currently I am busy with other stuff, so I just wanted to point that out.
See the docs about alarms (import alarm)