Protolife occupies a rather special place in my repository of tower defence games for two reasons. First, the central concept of controlling a little construction bot that poops out blue blocks in specific patterns to create all your defences. It’s neat, it’s elegant, and it places you into Protolife’s world in a way that few games in this genre manage. Secondly, it’s better than pretty much anything else at teaching you how to play tower defence games – or even strategy games in general.