Just my humble 2 cents, mentioning I haven't come across any bugs via Harmony Encore on my Woody and no issues via Stella either with RC6, as well as a brief comment...
What really grabs me (You know, besides everything about this game) is not just the way the graphics were ported over for the system, the very accurate scanner/map, wonderful sound effects and speech, the plethora of options, but also the depth of field feeling effect.
The flickering stars truly appear to be off in the background distance, while the layer of sprites appear to be in a very close foreground. I know it is just an illusion of sorts, but it is pulled off so well there is a pseudo-3D effect that is uncanny. I'm trying my best to think (Or better yet play), any other 2600 game where this effect comes across as prominent, but nothing else comes close.
The way the screen appears to scroll is truly remarkable. I still find myself going "wow", every time I play.