To make a Minecraft analogy that more people might understand, is it closer to redstone or command blocks?
There are three types of combinators: arithmetic, decider, and constant.
Signals have a channel name (one for each item type and a few dozen other options) and an integer value.
Arithmetic combinators can perform arithmetic operations on one or all signals with one signal and a constant integer, or two signals.
Decider combinators perform comparison operations.
Constant combinators emit constant signals on a given channel.
There are also abilities to detect state on some other items and cause behavior to change, the equivalent of observers, dispensers, pistons, etc.
Mid to late game you also get construction and logistics bots. The former allows you to copy/paste groups of machines (bots will make them), and the latter of which just makes sure you have things that you need in your inventory. Bots speed the game up quite a bit.
It was fun figuring out how to make an automated system that feeds nuclear reactors with fuel to supply my base with just the right amount of steam for the generators, signaling an alarm in case of over utilization.
When Factorio items are wired together with signal cable they have a few different operating modes. You can specify what objects are requested from a delivery network and what items are taken from a chest, or if any are to be taken at all. So this solution involved chests being filled with various items that have a specific color on belts, and then staggering pulls from the chests to place on belts in such a manner as to make pixels.
Those commands were issued by combinations of the constant signal block, the comparison/decider block, and the arithmetic block. I would say those entities are between NAND gates and pre fabricated if/else or for loop constructs.
So something in-between.