he's right.....I think in games you'll need to understand the concept of things, so if your game will have knowledge in the physics of the universe, so look up the birth, life and death of a star, look up white dwarfs, red dwarfs (And not the weird TV program) red shifts etc. heck I'll pull out my revision guide but it doesn't contain much on this part of the course, so bare with me.
So if its gonna have a red sun, make sure its not in the center of the universe, bad idea.....(supposedly, I think its our galaxy that is orbitting a black hole 100 times the size of our sun....see kids you should watch the discovery channel
)
The death of stars like our sun:
first the star turns into a red giant (Red Sun) as it expands (like a really slow giant explosion) in which becomes a nebula, then a white dwarf, want diagrams, google it.
As for much larger stars:
it goes red giant - supernova, and the next bit varies, it can either become a black hole or a neutron star (star only made of neutrons)