For those who come from a Factorio background, Mindustry has less automation and more combat. Also a Mindustry map does not take 50 hours to complete; rather it will take a few hours and may sometimes take several tries as some maps can be fairly hard. Space is limited as compared to Factorio, so space-efficient designs do matter, especially for defense (you want to pack towers tightly, with the constraint that towers must be fed by a conveyor of ammo or a pipe of liquid, or both). You also need to consider that you often need different combinations of towers in order to defeat different types of enemies.
Overall, a very well-made game and very addictive.