We were playing the 3rd round of intermediate and he generated the map with wkterrainsynch. I think the proportions are 1.5x 1.0x. As the replay shows, the game starts with the worm falling immediately in water from the sky.

Is there a sort of explanation why this happened? We are both curious about that 

Maybe you need the terrain to play it. Here's the one I've used in the attachment.