To get this achievement you will need to bomb a planet with a protobomb. By the looks of things the developer removed the event that is giving the bomb. So first you need to download the old version of the game using depot downloader.
This manifest Id worked for me: 4216160508608933087

Next start the campaign and there should be an anomaly next to your starter planet. It should be this:
https://steamuserimages-a.akamaihd.net/ugc/2453979462050684935/283939D35794FBC49650584595B37E4E8A2F83AD/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

Choose any option that give you a special project.

Next after the research is complete you will see this popup:
https://steamuserimages-a.akamaihd.net/ugc/2453979462050692663/F27551DC22F895DAAD11FEC34B3FA0CD1823BA15/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

Choose the "test subjects" option and you will gain a protobomob after some time

https://steamuserimages-a.akamaihd.net/ugc/2453979462050698370/5AFACA4344E46E1BD567E79FE50DE9C4B62A7973/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

Now simply equip the bomb and bombard any populated planet (minor races work too).