[Suicide Junkie]

Minor suggestions:


1) is good
2) the 8 surounding squares doing 200 damage sounds good, but for a star, you should have the star's square only do the 200 damage, with 50-100 on the 8 squares around it.
3,4)Black holes are really easy to detect when you're close (astronomically). If you're in the system, you'll notice a star's worth of gravity plus a great accretion disk in many cases. If you're plotting a course, you will definitely notice whats happening.

Planets are perfectly OK, as long as they somehow survived the creation of the black hole (likely creation: supermassive star dying)
Maybe asteroid belts that can be formed into planets?