I really start to think that Supergiant is making games about relationships after playing both games.

Bastion is about moving on from a failed relationship where no matter how you try to salvage it, ie: NG+, the relationship will never be the same as before which can be seen that Calamity will reoccur if you choose to restore Caelondia with hopes that things will be the same as pre-Calmity. It wont, and Bastion is trying to say that you need to move on from it. Until you move on where you fly off from Bastion with your survivors then you had moved on from it. I admit that Bastion did not make it as clear as you could see other themes in that game like war and forgiveness.

Transistor, on the other hand, I think the central theme is a lot more obvious. The game is about if that person is meant to be with you, no matter what happen(including the Process going rogue that ended the world while Calamata is going insane), you'll find yourself being with that person at the end. Note that I have not played NG+ yet but I am expecting the same as Bastion to enforce their themes. Also, it feels like Transistor is trying to demonstrate that it is better to lead a simpler life with the people/person you want to be with than having all the power and wealth in the world alone. This can be seen that Red rather "kill" herself with the Transistor to be with the Man Stuck in the Transistor for a simpler life at the farm lands than wielding the full power of the Transistor to change the world to her liking while being in Cloudbank alone. That part made me teared a little bit.

This is definitely one of the best games I had ever played. There are faults such as cookie cutter weapon loadouts in Bastion and some annoying enemies in Transistor because there is no perfect game in the world. Still, both Bastion and Transistor are god damn amazing games.