Shame you can only reset (buffed) once... I would have replayed until it was a joke reaching the final node... such an enjoyable little game...
Whenever I tried, it put me back in a fully unlocked map gaining billions of light per second... but it DID start with the opening brightness that tells you about the game for a few seconds... I tried running back to the endpoint and picking again, but no change...
First time I did it, it put me in a fresh run with 2x light gain... 2nd/3rd time it just put me back in the finished buffed run...