So you made it through the Intermission, eh? I guess that means you’re ready to get all Act 4 up in here.
Act 4 opens on the first truly interactive panel of the story. John, having made it through his first gate, has found himself on the surface of the planet Sburb has conjured for him, the Land of Wind and Shade. While here, you can wander around, talk to the salamander inhabitants of the planet, and battle imps. There are some important story elements that come out in the playthrough panel, by the way, so if you wrongly assume (as I did) that this was just for kicks and you could move on to the next panel any time, think again. And if you find the gameplay tedious, you can always cheat and watch a walkthrough on Youtube.
John spends most of this Act messing around on LOWAS and getting his chain yanked by trolls, who show up in full force for the first time; however, near the end of the Act shit starts to get real again—real timey-wimey and complicated, that is, as something John does has effects reaching back in time, setting up the whole reason he and his friends are in the game to begin with.
Rose has also entered the second gate, and her house manifests itself in the Land of Light and Rain. She investigates the surrounding area and does research and recon for most of the Act, rather than actively seeking out any adventures.
Dave and Jade are both in the game at this point, but they have not reached their gates. Between the two of them they figure out a bunch of hacks for the game, so from this point onward things like grist limit don’t really restrict the kids’ ability to alchemize stuff. They spend some time dicking around and making random stuff out of their belongings. Kernelsprites are prototyped, new powers are experimented with, and tension escalates for both of them despite their being not as far in the game as John or Rose.
Act 4 is the first time we really get a grip on the trolls’ separate personalities, although for the duration of 4 we only know them by their screennames (as well as their text color and typing quirks). They each seem to have different motives in ‘trolling’ the kids, but their position outside the kids’ timeline means that they’re often instrumental in revealing key plot points, such as the kids’ larger roles in the game: John is the Heir of Breath, Dave is the Knight of Time, and Rose is the Seer of Light. Jade’s role doesn’t come out till later.
This Act also gives a ton more backstory for the non-human exiles in ‘flashbacks’ to the current timeline (remember, the exiles’ storyline is slightly in the future compared to the kids’). They’re actually former inhabitants of Skaia, and their current monikers’ initials are the same as their past roles’ titles: the Peregrine Mendicant was the Postal Mistress, etc. Outside of those four, Jack Noir, the character we briefly saw Dad Egbert fighting in Act 3, becomes a much larger part of the story.
The exiles’ adventures in realtime are actually crucial to the evolution of the storyline, it turns out, as each of them are in some way involved in the escalation of the game’s conflict, which takes place on the chessboard-like surface of Skaia. Each time the four kids prototype their sprites (twice for each player), the battlefield becomes more complex, with changes reflecting the nature of the prototyping.
During Act 4 the story reached its first anniversary of publication, which is marked by a recap of the events within the storyline, and Andrew Hussie’s first self-insertion as a character relevant to the storyline. Hussie’s being an actual character is one of those Homestuck things you just have to throw your hands up and accept—he doesn’t go away.
Act 4 is really the first time Homestuck lets loose and gives you a lot of action and plot forwarding, as opposed to the previous Acts which were more involved in setting stakes and worldbuilding. If you weren’t really feeling it during the first three acts + intermission, I encourage you to stick around long enough to give Act 4 a chance, because that’s where all the setup comes to fruition for the first time.
Check it out here, and remember, it’s dangerous to go alone: take this. (Seriously, though, the MSPA wiki is super-helpful if you find yourself confused by things like time paradoxes, ectobiological relationships, and/or Skaian political systems.)