Really nice job! The graphics looked great - did you do it all yourself?
I enjoyed the music and difficult to control truck. I found myself chuckling to myself as a rammed back and forth into the buildings. But I think it would be fun to take the time and master control of the truck.
A couple bits of feedback:
1. When I tried backing up the truck and turning, it would start actually moving forwards? Or turning the opposite way? Didn't always perform quite the way I expected.
2. Would be nice for a bit more feedback when the water is hitting the fire. Wasn't quite sure if I was hosing the fire or not until I saw the fire going down.
Also, just wanted to say I really appreciate you making a Linux download available :D
And wanted to note - when I tried downloading for Mac, I tried following the steps I've taken in order to open Unity games (https://answers.unity.com/questions/1377896/the-application-cant-be-opened-mac-b...), but for some reason got an error: "'Firefighter-macOS' is damaged and can't be opened. You should move it to the Trash."
Good work!