I love this gorgeous and evocative little time waster and come back to it every now and then. Notes:

It starts out buttery smooth but over time its performance slows to a crawl. Changing window geometry seems to do some sort of garbage collection and it speeds back up. I just hit F11 twice real quick.

The optimal strategy is to try and make the trip parabolically with a single large burn at liftoff.

Gravity physics is of course symmetrical on ascent and descent, so the optimum time to start your deceleration burn is approximately when your downward velocity is equal to whatever your upward velocity was when you stopped burning.