So, when I first hopped into the game, all I did for a few hours was just play with planets and collisions. After a while, I wanted to test my knowledge on the actual advanced workings of stars and black holes. "A quasar, I'll make a quasar!" I foolishly told myself, assuming that the game was that complex. I spent hours plopping down various types of black holes and setting stars and other masses into a radical orbit around the black hole, only to learn that, sadly, quasars were non-existent in the game.
Next, I tried to create a pulsar. I knew that some where in the game already, but I wanted to see if I could create one based on my knowledge of how they're born. But, to my surprise, neutron stars weren't in the game
It confused me that pulsars were in the game, but not neutron stars, as pulsars are a result of neutron stars.
There's also a minor issue that I take with some of the other features of the game, such as supernovae not completely obliterating everything near it, black holes not having anywhere near the gravitational pull that they should have, hypernovae (super-luminous supernovae) being non-existent, all of them are minor on their own but put together they generally decrease overall satisfaction.
Now don't get me wrong, I LOVE this game, absolutely, and will continue to play with planets as a god for a long time, but there's always room for improvement.