Hmm, so you're saying Rd8 is a bullet tactic. I guess so.
When I would play bullet I remember your brain automatically keeps a list of all possible threats. So for example after 3.Ke4 white would be aware of Re1 and Rd8. One bullet strategy/tactic is to pre-move a response if it can deal with all threats.
In that position, when there are two threats, white could premove Qb7 and then pick up the king and hover Kf5. No matter black's move your next will come nearly instantly.
I think this is a common strategy/tactic.
Whenever I come to a profile of a fanatic bullet player, I see that this person got overloaded by comments hitting on the lower end of fairplay.
But what I think is really intriguing comes to the less insulting comments with the subject of: "This person just plays on time."
If I think of my own bullet wins, a high number of victories I got by winning on time. Sure, the less time you have for a game, the greater are the chances that the game ends with a time ko. So basically, if you agree in playing a one minute game, you already agree to a high probability of having a time-related end set to it.
Two points have come to my mind regarding the question if bullet chess is an own chess version. My point is: "Yes it is" and to explain this I will focus on the two main aspects of the chess game, strategy and tactics.
Bullet strategy:
In a normal chess game, a good strategy accounts to the best positioning of pieces given the structure of the game (and possible later structures), which clearly involves in the decision of piece exchange. Since bullet chess depends on time as a rare resource, a good strategy in bullet envoques about time play. In the later course of the game, the player who has an attack against the king is clearly in advantage, even if in normal chess the attack fails.
In this position with little time and white to move, checks on the seventh and eight rank give him a strategic bullet advantage! The reason is that he can switch even to diagonal attacks, requesting a time loss for black when having expected horizontal ones.
Is this unfair? No, from my point of view. Bullet chess follows it's own strategic rules and they involve this time play criterion.
Bullet tactics:
Since bullet is, in terms of game theory, more a simultaneous than a sequential game (as chess in it's pure form), bullet tactics defer from chess tactics in the way that they take this speciality into account.
In normal chess, this which is considered by me a "bullet tactic" would have never worked, but here saved black half a point.