Please Help me I.D. a late 80's Computer Game

[EllertMichael]

Hey, friends. hopefully someone can help me find out the name of this game that's been bugging me for the past 20 years.. I'd know it if I saw a screenshot or video..

around 1989-90 I was around 4-5 years old and my babysitter's brother had this black and white computer game he used to play. it was a spaceman-looking character standing in Contra-like position with a gun. there were doors on the wall behind you that you'd pass through, and you could see both the top and bottom floors regardless of which room you were in

unfortunately i don't know what the computer was that he was using to play this game.. it wouldn't surprise me if it was an old Mac or Commodore 64

any leads would be helpful. Thanks!

[Krooner]

Sounds like a conversion of Elevator Action or Rolling Thunder.

[EllertMichael]

Sounds like a conversion of Elevator Action or Rolling Thunder.

certainly in that same vein..

[EllertMichael]

Bumpin' this! Help finally put my mind at ease...
Any ideas, guys?