NotThatHatGuy wrote:Of course, this being xkcd, he might simply have departed uphill to construct the launch ramp for whatever unlikely vehicle will imminently jump the castle and land on the ramp she is now constructing.
Good call... but he wouldn't say "bye" in this case.
Angelastic wrote:Regarding 5), I assumed this was just to set the scene, make it clear that there was water there and they were on a beach.
Yes. Good thinking. That strengthens the point 5.
However, it could also be Cherkov's gun - the water was shown as innocent at the very start of the story, just to erupt into a wave at the end (or slowly increase its height as a tide). I thought about it for a while, but... both theories won't stand.
That's because this is the beach. You don't see waves flooding the beaches unless it's a cataclysm (which it is not, as it would be the kind of "end of the world" ending when the scene is smashed to bits at the very end. Contradicts point 1). The tide, however, was a valid option... but think this through - how would it be presented? Water slowly rising with each panel, then going back. Considering the time flow (ha, ha!) within the story, it would take 8-12 hours to present such outcome, and we would know what it is after 4 strips. We would be bored by the next few hours. This strip isn't designed to present such story.
Although I have one alternative that is worth taking into account. That is - the tide is coming an both characters try to defend against it. It would be a great twist, especially now with the bigger castle being build. The story could show how the tide ruins the huge castle/raptor/thing while the small one prevails only because it's build higher. I can picture it being like that.
It would break the 5-th point though, and my hunch is telling me, the 5-th point is correct.