Under some rarely circumstances I was able to kill the last enemy hedgehog without using any of my weapons.

The hedgehog was standing closely to a mine. I was walking to this mine with one of my hedgehogs and quickly run away, when the mine was activated. After the detonation the enemy was blown in the water and so the game was (theoretically) won.

But the engine doesn't recognize this situation. After I shot in the air and so ending my turn, the game quits successfully.

Other circumstances may be possible, e. g. flames falling down, when nothing to burn are left, etc.

It's not a hot bug (game doesn't crash), but it's a bit annoying.