House of the Dead Overkill is on Steam as a bonus mode in Typing of the Dead Overkill, which is also great. There's also Blue Estate, which seemed pretty crummy from what I played. I do own Rambo (it looks like it's going to be removed soon -- the base price went from $20 to $3 which is never a good sign) but haven't played it yet.
I forgot about Overkill, I actually own it and have played it, I was thinking more of the main titles of the series.
Now I wish we'd see the other "Typing of the Dead" games.
I'll check Blue estate though, first time I hear about it, thanks.
I suppose for $1 I could do worse than Rambo, might as well just find out by myself.