Tropes that apply to all four main characters (Captain, Sniper, Pilot, & Engineer):
Ambiguous Gender: This especially applies to the Captain. Sniper and Engineer were both eventually confirmed male, but the comic's creator continues to be deliberately vague about Captain and Pilot (although Pilot is now implied to also be male).
As of the latest comic. If it is to be believed. Pilot is Male. Which leaves the Captain/Captein as the only one without a specific gender.
Loving a Shadow: Thinks Zee Captain to be a god, though Zee Captain is implied to not reciprocate (responding with flat dismissal whenever Pilot makes advances through the blogs, and having said that his "minions" are "all equally tolerable").
No Name Given: A name is written on his jacket, but he doesn't think it's his. However, the Biomass calling him by it and his wearing the jacket in a pre-apocalypse flashback imply that it might be, and he is just too far gone to remember.
Foe Yay: ANNET called him "dear" and said "I love you" whilst trying to kill him years ago. In her recent return she referred to him as "my love", just before trying to kill him. Likewise, Engineer usually calls her "Annie", and before the apocalypse it was definitely a term of affection. He also has called her "my love." He even wrote a poem about her, in which he called her "my beloved".
Only Sane Man: Type 3. Unlike Snippy, he's completely given up/accepting and doesn't even bother protesting the strangeness of his companions. Although one of Snippy's blog entries implies that he might not be all that sane after all.
Evolutionary Levels: The Cancer incorrectly refers to the Lifealope's shapeshifting ability as "evolving". In keeping with the trope, it seems to become more intelligent and complex with each shapeshift.
No Name Given: Unlike the other characters, it doesn't even have an In-Series Nickname. The closest thing is a wallpaper of it titled "WOLFALOPE." To compensate, fans have dubbed it "the Lifealope", a portmanteau of "life" (because of its Fertile Feet) and "wolfalope."
Shapeshifting: Started out as something resembling a salamander or lizard, then shapeshifted into a rabbit, then a fox/wolf-like creature, and then seemed to resemble a moose or deer before being killed by ANNET's ion cannon. It was reborn as a cat-like creature (a wallpaper by the creator calls it "CATALOPE"). The only features that have remained constant are its three eyes and the presence of antlers.