According to Jisho, だらしない has two definitions:
So, I think you could also probably translate that second sentence as “…someone as weak/cowardly as him!” I think I’ve also seen it translated as “useless” in anime subtitles before, so that was what my mind automatically read it as while I was playing. 
Right actually I didn’t see the weak, cowardly definition, and it definitely fits too. I’d translate it loosely as “being a loser”, perhaps.
Yeah I think that makes a lot more sense in context. She’s calling him out for being too afraid of the monster to sail - not his cleanliness or whatever I thought. 
Could be both! They are pirates vikings after all, who are not exactly known for their cleanliness! 
Ok but what about the edge of the map?
I found an interesting difference in the script for the 3d version. Instead of saying
宙に浮いたこの大陸を落とす (drop this floating continent), Medusa says この大陸を闇の星へと還すのだ (return this continent to the dark star).
Later, Desch says このままでは 浮遊大陸は太陽からはなれてしまいどうなるかわからない… (At this rate, the floating continent will drift away from the sun, and I don’t know what will happen…) instead of このままじゃ、浮遊大陸は 動力を失って落ちてしまう(At this rate, the floating continent will lose the power that moves it and end up falling). There’s a bunch of other changes, but these sound like large differences in the cosmology.
星 is often used to mean planet in games like these (since we’re aren’t on Earth, 地球). So it could mean Dark Planet.
It is a strange script change that renders the whole situation even more confusing…
I found it a really cool revelation and can’t wait to find out more about all the implications of it!
There’s a major plot line in FF14 where a group of heroes saved their world, called the Warriors of Darkness. The world you play in is just one of 13/14 that were split off from the “true” world long ago, and your character is often called the Warrior of Light. The dude you see on the cover of FF14 all the time is actually the Warrior of Darkness.
I’ve seen them mention darkness and light multiple times in FFIII so far, and I think I even recall a mention of 闇の戦士. FF14 pulls many of its side plots from old games. The final raid series of FF14’s first arc was the Crystal Tower. My understanding is that this was from FFIII, and the boss - one I’ve fought dozens of times, Cloud of Darkness - is also the boss of FFIII. The final stage of the raid, past the crystal tower, is the World of Darkness - 闇の星? It was one of the 13 original planet shards, which was completed consumed by darkness at some point in the past, and the Warriors of Light from that world are known to you as the Warriors of Darkness. I have no idea how much of this will actually be in FFIII.
It’s not even that darkness is inherently evil - I think there’s a part of the plot (Shadowbringers?) where you go to a world that is going to be consumed by LIGHT, with equally ill effects.
It’s not lava it’s Fanta