I'd like to start by saying this game isn't bad. It is well optimized, it always has goals to work towards, and the overall base mechanics are pretty fun, but my main issue is how quickly you end up reaching repetition, mainly due to how useless most of the upgrades and mechanics are.
The main 4 objects in this game are the belt, the bridge, the adder, and the multiplier. You get these within the first 10 levels, and every number can be made with these.
The last 4 mechanics are the subtractor, which isn't super useful when you're trying to make bigger and bigger numbers, the divider, which I never used, the exponentiator, which is probably the most useful of these 4, although suffers from how few unique numbers you can get from it, and the storage, which I literally can't think of a use case in this game, other than maybe storing the next level's number so you can get a headstart on the next level. Overall I pretty much never used these 4 objects because it's a lot easier to work with addition and multiplication, leading to the game getting repetative quickly.
As for the upgrades, the only two that are useful are the belt speed upgrade and the extractor upgrade. The belt upgrade makes your belt faster, it's obvious why that's useful, and the extractor upgrade allows you to extract more belts worth of numbers from their extraction points. The other 4 upgrades increase the speed of the adders, multipliers, subtractors, dividers, and exponentiators, but you can basically ignore them since you can just copy and paste a design with like 15 of them. The only reason you wouldn't want to do this is because of the like 10 extra seconds it takes for the belts to fill, but whether you use 5 fully upgraded adders or 15 un-upgraded adders, you'll still have the same outcome when it comes to the final rate of numbers produced, and unlike in other games where adding more machines is difficult, this game literally just does all the logic for you; as long as the belts face in two different directions, it'll just send half in one direction and half in the other.
Ultimately I don't think it's a bad game, but by the end I was just feeling bored of making the same machines over and over, and then just waiting to get to the next number in line. It's probably worth like 2-3 dollars since I'd say it has around 2 hours of good gameplay before the game really gets boring, but honestly I'd just recommend saving your money and spending it on a better factory building game.
TLDR: Similar to shapez, except it gets repetitive really quickly, with most mechanics introduced later on having very limited use cases, and most upgrades being nearly useless. Not really worth your time overall
