Two criteria need to be met in CO prior to using deadly force:

1) You must have a reasonable belief you or an innocent third person is in imminent danger of suffering death or SBI,

AND

2) You must have a reasonable belief that a lesser degree of force will be inadequate to protect you or the innocent third person.

Stand your ground doesn't apply in CO. If you have a legal right to be somewhere, you don't have to leave if confronted by bad guys. That's not to say that retreat isn't a perfectly valid option...it is. If you have the option to leave, then unass the area ASAP.

The next thing you need to remember after you whack the bad guy is what to say when the police show up:

1) "Officer, I thought he (or she, or they, etc...) was going to kill me."

2) "I want him arrested." (good to say even if the bad guy is ART...may help to show you didn't mean to kill and you didn't know you had killed)

3) "Officer, I want to cooperate fully with your investigation but I want to do so with the assistance of my attorney (or with my attorney present)."

Of course, you'll need to make these statements specific to the incident...but just a good guideline.