Very cool game !
The tank controls and camera placement felt cruel and funny in a very Barbuty way :)
///SPOILER///
I think I got the eggplant ending? I was confused at first with the softlock, then I reread your description!
I'm surprised that you say there are no softlock, as it felt very easy to lose the crosbow bolt.
Is it not required to finish the game? Is there another way to get it back?
I really liked the broken pillar under the bridge, a really cool revelation only made possible by the camera limitations.
I tried to use the knowledge later as a shortcut to the crosbow room, but I couldn't figure out a way to drop on it from above.