I've pretty much played through all the new content there is to offer....
Vulcanus
Great aesthetic, reminds me of Mustafar from Star wars.
The big mining drill is a nice addition. The 50% reduced resource drain is great on seeds with low richness. Before Space Age, I would never play on low richness, but now I'm reconsidering.
It feels pretty good to cast items in bulk with piped molten metal, but it also feels quite overpowered and oversimplified, especially being able to cast items like cogs.
Demolishers could use some work design-wise. No sane player would ever build in their territory, so basically they never attack your base. Either you have the weapons to kill it or you don't, and it's not that hard. Then once you have some territory unlocked, Vulcanus becomes super easy mode.
Gleba
Pretty good aesthetic. I like all the creative alien plants and fungi. It was a little overwhelming at first though in a good way.
The spoil mechanic was interesting, then I slowly liked it less and less.
I've seen some servers that have clever belt-only bases, but in my opinion, the amount of belt infrastructure that's required to manage the spoilage is not worth it over a logistics bot setup. My bot base is much, much smaller with significantly less spoilage rates. Ironically, I had to purposefully spoil items to increase carbon fiber production.
The new enemies here are exactly what I was expecting for a Factorio expansion. 8/8 work!
The new stack inserters from this planet are one of my most favorite parts of Space Age. Personally, I really don't like massive megabases. I like small and compact, and these inserters do exactly that.
Biolabs look great, but they're just better regular labs.
Fulgora
Aesthetics is a little lacking. The oil ocean and monochrome color choice could be spiced up a lot. Ruins could be further developed. I had imagined there would be still-functioning semi-ruined bases that produce hostile mechanoids (maybe a mod idea?).
The lightning mechanic is trivial, solved very quickly, nothing more to say.
To me, scrap and recycling is gimmicky and overpowered. Mine some scrap and it recycles into blue chips and low density structures. Think about the long production chain that goes into crafting a blue chip. Scrap completely skips that. It erodes at a foundational pillar of Factorio in a bad way.
It almost feels like the devs shoehorned scrap and recycling into the game to introduce quality. Fulgora is the perfect place to do quality crafting, as you can place quality modules in the recyclers. The quality modules themselves are also unlocked here.
Quality
I can see why the devs implemented Quality as a separate mod from Space Age. On one hand, it's unnecessary bloat. On the other hand, it's a pretty neat endgame grind, and it did feel amazing when I got a legendary mech suit on Fulgora.
Maybe my opinion of Fulgora has ruined this feature for me. If scrap recycling were designed differently, then a player's natural progression through the quality grind would also be different. Maybe I'll develop a mod that redesigns Fulgora and Quality.
Aquilo
The aesthetic is slightly better than Fulgora but still lacking in the same way. Again, there are no hostiles; I had imagined perhaps floating icebergs (similar to asteroids in space) or giant squid attacks.
Heat pipe mechanics were very annoying at first. In essence, Factorio is also a puzzle game. This mechanic just adds another dynamic to the puzzle. Once I got used to it, the puzzle was solved. Maybe my designs could be further optimized, but it is solved. It makes base-building more restrictive, and I'm neutral to this, but some players may hate it.
It's very evident the devs took inspiration from the sea block mod. Personally, I never enjoyed that mod. Filling in that ocean square by square just isn't appealing to me. It's an annoying, thoughtless, slow grind. I don't see the appeal. Maybe if there were a hostile element to it.... Maybe the more you expand and cover the ocean, the more likely you are to attract hostile attacks from below, such as a giant squid.
The tech additions here seem a little superfluous. Railguns are only necessary for getting to the solar system edge and shattered planet. Fusion reactors are like fission reactors but better and more compact. Nothing here really changes or improves the way you play the game like the other planets do.
Since Aquilo uses materials that the other three new planets produce, I'm thinking Aquilo is kind of an afterthought planet. It's not a planet that stands on its own, provably by the fact that it doesn't have any iron or copper. Things must be imported.
Honest question, did the devs run of time and rush Aquilo? It feels like wasted potential. Mods please.
Space Platforms
An expansion titled Space Age really does demand spaceship building features. It does deliver.
Shooting asteroids and collecting them for resources fits Factorio perfectly. It builds on everything in the base game in a well-designed manner (unlike Fulgora).
Platform mechanics are pretty free-form with minimal restrictions. I really like that I can build a ship in any shape and form I want, as long as it doesn't die to asteroids. This is the real endgame, building a massive self-sustaining Death Star. Mods could definitely expand on this.
However, there are some minor annoyances. No chests allowed, but belts are fine? Inserters don't work with cargo bay attachments? Buggy asteroid collectors?
Shattered Planet
The way it's shown in the star map, I assumed I would be able to land on pieces of the planet and build a base, like a secret 5th planet.
Unfortunately, according to Youtube videos, it's just more asteroids space, nothing to land on.
So I stopped building a ship that can reach it.
Big disappointment.
But it's clear this is where the next expansion will come in. Factorio 3.0 when?
Overall
Very nice expansion, lots of great new additions and appropriate powercreep, although some features are either questionable or undercooked. 8/10.