itch.io

No worries!
Just a progress bar to show the next destination if there is one. 
Conversely with your goal of no ui. There could be a sensor on the truck that detects a "safe zone" to rearrange some elements on the truck without the zombies coming.
It was really great overally, I really like the lore as well. 

I believe the "no ui" approach gave the game its own touch which made it stand out from other games. My opinion though.