Yoji Yamada's Falling Down, except it's a slapstick comedy (for the most part) and also not much happens in the first half.
At least The Donkey Comes on a Tank picks up a bit in the second half, when that tank actually comes into play, with a bit of a comedic rampage playing out in a small town. It's funny until it's not, and the tonal shifts are handled well, as they usually are in Yoji Yamada's stuff. Before then, the most interesting thing going on is the structure of the film, with the story playing out from a tale being told on a boat.
It's a minor Yoji Yamada film, but I'll still watch anything the creative mind behind the Tora-san series made. And of all the obscure movies he's made that I've managed to track down, I think a few have been worse than The Donkey Comes on a Tank. What a title, too. I love typing it. The Donkey Comes on a Tank. For a while, I was worried it'd be just a metaphorical title, but thankfully, there was indeed a tank.