Its basically SpaceChem 2 in everything but name and theme (notice the bonders/mergers in the gif above? Those concepts should all be very familiar to you). I thought it would be closer to Factorio based on the trailers (Fantastic game btw), but it really is SpaceChem. If you like SpaceChem, you'll like Infinifactory.
Now that this is out of the way, there are some differences and some concerns I initially had that I should talk about.
Content:
First of all, compared to the neverending content of SpaceChem, this game doesnt offer quite as much (yet). SpaceChem got a ton of added content down the line and from what Zachtronics is stating, the "Early Access" is mainly used to add some more mini-campaigns and content ideas. Apparently, the current EA version has the COMPLETE main campaign already in a finished state, so I would actually consider it a finished product now with some free DLC hitting whenever they get to it.
These games are slightly devious when it comes to putting an hour count on the content. SpaceChem only had 40-50-ish levels as well, but the last few might take you several days to solve, so I am not too concerned about not getting my money's worth even with "just" the main campaign.
Graphics & Sound:
Lets get the elephant out of the room: Working out solutions in 3D works rather painfree. There are some initial moments of bepuzzlement, but overall, the UI and control scheme is very well thought out to remove possible annoyances. One example: If you hold down the left mouse button, you can build elements in a row (without deviating to the side), on top of those elements being turned to fit the movement direction of your mouse. Small thing,but very user friendly. The ambient sound design is very satisfying, the graphics are pleasing to look at (I love the painted background) and the soundtrack is reminiscent of SpaceChem and very good.
Mechanics:
Now this is going to be fun to explain. Many mechanics/blocks work very similarly, but SpaceChem was different in a few key points, for example using chemistry as a theme (which Zachtronics confirmed as being a design mistake as it limited the appeal to general audiences) and most importantly: being a top down map. The change to 3D does not only bring some slight control confusion but also changes and adds mechanics. There was a certain beauty to using a single space in SpaceChem for multiple actions, which is a feeling of ingenuity I am missing so far in Infinifactory, however, Infinifactory has some new tricks up its sleeve. The addition of height, makes for some genuinely new problems that need to be solved. Instead of just being more SpaceChem, different heights and the considerations that come with that actually add a TON of depth (ha!) to the mechanics. Stacking elements, stacking constructs on a conveyorbelt to have it to things in multiple parts of the level without rebuilding it... there is a lot that I have yet to discover and on top of "Oh fuck yeah, more SpaceChem!" the possibilities that this is opening are very, very exciting to me.
Accessibility:
While still being very similar to SpaceChem, realizing this game concept in 3D will actually make it much, much more accessible to players. Structures and production lines are easier to make out, the 3D itself is a good selling point for a certain part of the gaming populace, and building something in 3D and seeing all the gears working might just turn out to be even a tiny bit more satisfying than it already was in SpaceChem.
I'll come back here for more impressions eventually, but for now: Easily worthy entry into the GOTY list of 2015 and if Zachtronics adds some more levels, mini campaigns and other shenanigans, Zachtronics will likely top my GOTY list once more.
I can't give you any reason not to buy it. It has enough content as it is, clever level puzzles, well thought out UI/controls, pleasing graphics, great soundtrack, is more accessible than SpaceChem without losing much of the complexity, adding a whole new range of puzzle ideas (height) and more content on the way.