I have not seen Adventure Time, so I can't make any comparisons.

I hugely recommend it as it's possibly the best TV cartoon series of all time. (It makes me envious that we adults can't have TV animation that compelling.) I think it scratches a bit of the same itch as Undertale does. They're both deceptively simple as their visual style signals (correctly) that they are often comedic and light-hearted, both examples of that being cute and compelling aren't mutually contradictory. Both of them were game changers in their own mediums in that they make you view their mediums in a new light. They both also have genuine themes, which while perhaps aren't unprecedented, are treated in a novel way, like Undertale does with the theme of preconceived notions. There are characters, much like Alphys, who have way more meat to them than you might think at first. There's a ton of lore and basically any detail might turn out to be significant in the end, yet many things are left unexplained, which I as a habitual overthinker find very satisfying. Both have clear queer themes, as well.

One way to describe Adventure Time on its own terms would be as the growing up story of Finn the Human, the last human to live on Earth after apocalyptic events, living in an odd ball world of monsters and candy people. The show matures with him, starting out being a zany and eccentric spin on fairy tale tropes, yet grows up a ton while developing an unique blend of episodic and serial storytelling over the seasons. It still retains its gentle and sympathetic core onto the end, distinguishing it from most adult fare, but it's a lot more sophisticated than children's stuff usually is.

Hayao Miyazaki's works occupy a similar place in film world. There's plenty of empathy to go around, things are rarely black and white and taken as a whole seem to propose an appealing attitude towards life, warts and all. Continuities between the episodes that reward observant viewers, metaphorical treatment of things such as dementia and memory and gradually deepening characters and their relationships hold up to adult standards (IMO), but children kept tuning in for 11 minute episodes thanks to their plots, voice talent, comedy and clear emotional moments.

That said, Homestuck definitely revolves around certain themes, many of them emotional. I don't want to spoil things too much, but a lot of these things are pretty timeless. I recently re-read Homestuck (i.e. in the past year), and it holds up well.

I'm very OK with spoilers, actually. Give me some of that delicious spoiler juice, if you want to, just don't tell me (much) about the latter half of the plot.

I will admit, there's definitely a value to having had been there to discuss, speculate, and theorize with others. It gives one time to digest and metabolize each update, a forced pacing that one might not get when reading it straight through.

Well, on the other hand I can read through it as fast as I want to, thus catching up is pretty fast.

If you're interested in Homestuck, I wouldn't want "being late to the party" to be the reason you don't read it. I was late to 17776 but it was (and still is) a great read. (BTW, if you like Homestuck, you might like 17776.)

When I put effort into consuming media, I'm often doing so in an attempt to understand other people better. Watching or reading something lets me enter conversations I wouldn't otherwise have had, which is cool and rewarding. Besides, Hussie seems to be pals with people I like from different circles (web comics people, indie game developers, cartoonists etc.). In fact Hussie's pal Ryan North has written Adventure Time comics.

I'm actually a huge fan of Jon Bois, though I have yet to read 17776.

oh you would love adventure time