As far as counters go in the game of Starcraft 2 siege factory play is as much of a counter to marine/marauder as you can get. But people are drawn to the marine/marauder style. Initially people thought it was because you just A+move your army and it does well. But at higher levels it becomes because marines and marauders can be microed effectively against almost anything.
Marines and marauders are harassment units. They are mobile flanking units. They are units that can be split off into command groups. They are units that can quickly split against area of effect damage. Marines and marauders are high damage units.
In this post I am going to list off a few tips for using marines and marauders against factory terran.
Tip #1: One Base Up
When you are using marines and marauders always make sure you are at least one base up on your opponent.
The marine/marauder style is a macro terran style. The idea here is (think like zerg) you can remake your army faster than your opponent and so if you are trading inefficiently you can rebuild your army ball very quickly and put on the pressure again. It means that the unit’s lost tab is going to be pointless as you will be re-maxing very quickly.
If you are one base ahead of the factory terran all game you will have 4-5 more unit producing buildings than him all the time.
Tip #2: Arch Building
If there is one habit you should build while playing marine/marauder in any match up it is building an arch of attack.
Whenever your units are clumped up run away from your opponents and make two slices. A slice is a partial selection of units. Your first slice will be your eastern units and your second slice will be your western units. Have those units move fairly far apart from your main ball. This way when you push forward again it will take them less time to line up and they will not clump nearly as much. In larger army sizes you’ll want to slice more often with the same basic approach.
The idea is that your small slices are going to land to create an arch of attack.
Considering siege tanks have an area of effect attack you should never engage not in an arch. If you A+move in without any sort of organization you will always lose.
Tip #3: Know where his army is
Whereas your army will be very mobile and all over the map, his will be bunched up in a single location.
Siege tanks do very poorly against marauders in smaller groups. Siege tanks are that unit you want clumped up into a giant ball. Terrans will generally try to create large giant positioned archs of siege tanks.
You never want to run into sieged tanks unless you are maxed and have tones of production to re-max very quickly. If you are scanning for tank positions before you are moving you are more likely to catch them off guard and make your hits at proper times. Also having tower vision will help a tonne.
Tip #4: Harass Addons
Marine/marauder/medivac is akin to harassment. Ever time someone harasses they immediately think that they have to hit SCV lines… which is good.
Removing reactors and tech labs will pay off a lot longer in the late game. This means they will be spending a lot less money and expanding more. This means that their army will be split up a lot more often and you will have more opportunities to hit in smaller groups.
Alternatively it could mean they are forced to make more unit producing structures than they can possibly support to try and catch up on their army count. Going after SCVs sounds like a great idea, but going against a guy who is primarily using gas his SCV count will not need to be that high.
Removing production means that when engagement happens he will be less likely to re-max faster than you.
Tip #5: Get Gas
As far as MMM goes your gas costs will go into 25 gas per tech lab for your marauders and 100 gas per medivac.
This means every upgrade you get is one less medivac or four less marauders.
A lot of people think because they are playing bio it means they don’t have to get gas. Quite the opposite. Ideally you will want more marauders in your mix than marines. But actually because there are so many more minerals than gas you will always have more marines than marauders.
The extra gas can be used for getting consistent and very good upgrades. You will need 1100 gas to get your infantry upgrades, 100 gas for combat shields, 50 gas for concussive shells, and 100 gas for stim pack.
That’s a lot of gas. After you’re done all of your upgrades your best bet is to lay down more rax with tech labs so that you can get even more marauders. The larger your marauder ball gets the better your big engagement will get against tanks.
Hope this was helpful, if not the video will provide a more visual look on these concepts.