When making the original Mortal Kombat arcade game, creators Ed Boon and John Tobias decided to create two palette-swapped characters, in order to save valuable space. Those two ninjas became Scorpion and Sub-Zero, and Boon and Tobias looked for a number of small ways to make them feel different to players. In a behind-the-scenes video Boon shared to Twitter today, we can see the actor that plays Scorpion and Sub-Zero trying out different stances, following suggestions from Boon and Tobias. The decision required an extra seven frames of animation, but the move helped to further distinguish the two fighters.

Continuing our celebration of Mortal Kombat’s 30th anniversary, here’s another video showing more behind-the-scenes moments. This time you can see how we decided to give Scorpion & Sub-zero different fight stances so they would look & feel like two separate characters. pic.twitter.com/t8fJmYexcu