It seems like this DLC has been rather positively reviewed so far. Due to moving houses and a new job and generally being busy with life I haven't played through it all so far, but I thought I'd rant a bit about my displeasure here. I think I've played through enough of the DLC to form an opinion of it, at least.
First, let's start with some positives.
Despite its nonsensical setting (why exactly did the terrarium have to be underwater, when the inside behaves exactly like a location on land?), I think the Great Terrarium is easily the best-looking overworld we've ever seen in the mainline Pokémon games. Okay, there are only four different biomes, but they are gorgeous. From the sprawling savannah to the cliff maze of the Canyon biome, the lush tropical setting, and the snowscape of the Polar biome, these look great, and all much better than mainland Paldea. It's as if the overworld modelling team finally managed to get the hang of building 3D locations, which makes me excited for whatever they have in store next. It's not just the visual appeal of it either, but the layout is excellent too. The terrain is always varied and distinct wherever you are in the four biomes. No place really look like anywhere else. If you care to look for them, there are multiple sub-biomes, like the Lion King rock in the Savannah compared to the mud flats, the cactus fields, dry flats, and canyons. Likewise, there's a great deal of variety between the freezing mountaintop and the iceberg-riddled bay of the Polar Biome. Bit of a shame that the Pokémon spawns are the same all over the place, though.
And of course, the fifth pseudo-biome, Chargestone Cavern. It's as if Game Freak is apologizing for the Galar Mines. This is what a Pokémon dungeon on the Switch is supposed to look like. You can easily get lost in its depths. There are giant caverns, narrow passages, monumental crystals, Galvantula webs, and a layout that takes full advantage of three dimensions. I wandered around there for ten minutes yesterday, trying to find the exit.
The writing is getting quite good too. Nothing that will win industry prizes any time soon, but it's certainly less wooden than previous generations. Things have certainly improved since Sun and Moon interrupting gameplay every five minutes to tell you something you already heard three times before. The developers are clearly letting go of the the players' hands to a greater degree than before, and having more fun fleshing out characters. The designs of the new characters are also complemented nicely by their unique animations. Back in the sprite-based days, all you had to show a character's, well, character was their dialogue. But now they can show more and tell less. Wonderful.
Speaking of letting go of players' hands and trusting them to find things out for themselves: the battles. It seems like the first time in forever, we've got some really challenging foes to fight. An all-Doubles extravaganza filled with opponents that use actual strategy, complete with using held items and Abilities. Even random trainers can wipe the team of an unprepared player. This is exactly what I've wanted since the days of Colosseum and XD: Difficulty and strategy. And not like the "artificial" difficulty of Raid Battles or Totem Pokémon either, where the opponents have seven different moves, a bajillion HP and can nullify stat boosts whenever it feels like it. These are honest, even fights where the NPCs use the exact same tools as are available to the players. No shenangigans, just raw team building, back to the basics of the franchise.
Actually, I have to talk a bit more about the difficulty, because it's such an important point: these battles are not insurmountably difficult. They can be steamrolled with an overlevelled team, or a team of specially tuned counters. Or possibly also some cheese strategies. But it feels like the NPCs now make an actual effort in battles, instead of just keeling over and fainting when the player comes knocking (Gen VI was especially bad here, but the past two gens have committed some sins too). The player always had this wide toolbox of tricks to boost and enhance their Pokémon, but the in-game opponents always refrained from using them. This gave players a massive advantage, to the point that it was way too easy to get ahead of the power curve and just steamroll the game with STAB moves. Victory was all but guaranteed when the in-game bosses used three bad Pokémon with incomplete movesets, poor IVs and no held items. That gave a sense of the games being way too easy. You won whether you made an effort or not. Oh, how we pined for some proper resistance from the in-game story. Well, here we go. This is exactly what we've clamored for for so long. And I'm having a real blast. Sure, I win the battles with relative ease still, but at least it feels like I'm battling competent opponents instead of just flattening cardboard obstacles. It feels great. More of this in the future, please!
There's not much to say about the new Pokémon since they are so few and I've yet to encounter any of the legendaries, but I'm going to say much anyway, because I really like the two new non-legendary Pokémon. I freaking adore three-stage evolution families, so it was really sweet to see Dipplin get that extra evolution. Applin is a three-stage 'mon now, and hence a sought-after catch in the early-game. Granted, Hydrapple's evolution method is as dumb and convoluted as they become, but that's mostly a problem in this game that can easily be remedied in the future (like by having Dipplin learn Dragon Cheer by itself instead of it being a random TM). I also feel bad for Flapple and Appletun, which are now completely obsolete compared to the considerably stronger Hydrapple - on top of losing their GMax form. But I guess they can remain somewhat viable in future games, by making the Sweet and Tart Apples available earlier than the Syrupy Apple. This creates a trade-off: do you evolve Applin early, losing out on its most powerful form, or do you keep it weak for longer? That could work.
As a side note, the Applin - Dipplin - Hydrapple family is now the second three-stage family of Dragon-types that is not a pseudo-legendary family. The Axew family was previously the only one to hold this distinction. I think this is a great plus for variety overall, because pseudo-legendaries tend to be mechanically quite similar to each other. It's also the tenth three-stage family of Grass-types not to be a starter Pokémon, because somebody at Game Freak must love the Grass type as much as they hate the Ice type (for comparison, there are two three-stage Fire families apart from the starters, and five for Water).
Moreover, I find it fascinating and promising that Game Freak created a cross-generation evolution for Gen VIII 'mons already. One would think those were reserved for old Gen I and II Pokémon, or generations up to V at most. But clearly, Game Freak seems to have realized they can spread the love a bit, and I think it is fantastic that they choose to give additions to even their most recent designs.
Then there's Archaludon. It's interesting that Duraludon, with its very high BST, was given another shot at greatness with an evolution. Archaludon reaches pseudo-legendary stats and has a very wide movepool. A real powerhouse indeed. This makes the whole evolution family very slanted towards the late-game, however. I hope for Duraludon to receive a pre-evolution too at some point, so players can pick it up at an earlier point in their future playthroughs and use it all the way to the end. Pre-evolutions made the Magmar and Electabuzz families very accessible for in-game playthroughs, so here's hoping they give the same attention to Duraludon.
Right. There was supposed to be some displeasure too. I promised a rant, didn't I? Well, it's freaking cold outside, and my current house is poorly insulated. I'm freezing! Time to cuddle up underneath a blanket and play some more Indigo Disk.