"Isn't the argument too anthropocentric? What if some kind of alien race constructed the super computer that simulates our universe, and the simulation was made to simulate mainly their kind? In this double-what-if scenario (we are simulated, but by an alien race that has nothing to do with humanity), what are the possible implications to your original theory?"

Formally, the simulation-hypothesis includes the possibility that we are simulated by an extraterrestrial civilization. However, the inclusion is redundant. If the simulation-hypothesis is true, then we are living inside a computer, and whichever civilization built that computer is our "home" civilization by definition.

Of course, it is possible that the simulators and their ancestors are more similar to some extraterrestrial civilization in our universe (if there are any) than they are to us, so in that sense it is possible that we are simulated by the descendants of an alien-like civilization.

More generally, simulators might create many simulated people who are very different from their own ancestors, or who live in worlds that are very different from the one that the simulators live in. It is possible that we are living in such a simulation. I don't know of any way of estimating the probability that our hypothetical simulators (or their ancestors) are similar to us, or that their world is similar to the world we experience. (The original paper focuses on ancestor-simulations because the methodology is more solid for that case. It is less clear whether some kind of principle of indifference could also be applied to a reference class of "observer-moments" that are very different from one another. For more on the reference class problem, see Anthropic Bias.)

References:

N. Bostrom,

Even if this is a simulation, I don't think it would make our experiences any less real.

oh... simulated. I misread that.

Never mind.

And maybe we're simulating the entities in return? I hope they're happy.

I think its possible that this matter reality and everything in it grows out of an energy matrix that permeates the multiverse. Its not necessarily a simulation. A simulation only in the sense that it may have once existed in a similar form with different variations.

perhaps very old highly evolved energy beings created a matter reality with all the things in it.

Once upon a time they had bodies and lived in a matter reality like ours but eventually evolved and advanced out of that just like we will eventually do.

Perhaps they are perpetuating the cycle. Perhaps we are a sentimental homage to to something they once had and can no longer have.
Perhaps its the big cosmic joke and really the truest representation in the universe of perfection is imperfection.

What happens when you reach a singularity of complexity as a lifeform? can you ever go back?

Perhaps our imperfection, pain and suffering is just the incubation period leading to a higher level of consciouness . One without a physical body only our compact sense of self as a pulsing unit of energy. Its possible that all great religions had it right all along

Perhaps extra terrestrials have nothing whatsoever to do with our existence and our destiny and this just IS the way it is. Perhaps the cycle of life is much longer and bigger and weirder than we could ever imagine.

With our current level of hyper-advanced technology and the way its exponentially increasing on almost a daily basis, at this point the possibility of us being that embodied race ready to jump off into the world of simulation is a very real one. Maybe once we realized how to create the program we break free of it? Or perhaps its just the cycle repeating over and over again, a simulation within a simulation within a simulation... Interesting thought project, thanks for that one!

Maybe we keep running simulations to figure out how to avoid sending ourselves off into the world of simulation. Or to discover how to escape once it's happened!

Off the top of my head I come up with this pseudo-science musing:

Can our universe be considered a universal Turing Machine?
Even if the answer is - not quite - I would like to consider this as an example for the time being. You can emulate a universal Turing machine by any other universal Turing machine, even if they initially don't appear to work the same way. They can be made to do the same things, calculate the same answers or give the same results... whatever. The point is, the structures that arise, or the patterns that emerge are essentially the same. Or rather they are indistinguishable from one another.
I wonder therefore, why it would matter if we were a universe, nested in another by merit of some super computer simulating laws of nature, or if we are a universe not nested, and the complexities and consciousness arose simply by merit of the natural laws as they are.

Very complex patterns can emerge from very simple rules. Chaotic ones, but also structured ones (i.e. reaction diffusion equations such as FitzHugh-Nagumo equation). The parameter range for these patterns to emerge is rather small though. There are certain magic numbers... I suspect it is no different with the universe itself. If the constants like Planks constant, the speed of light, the permeability of the vacuum etc. and the laws of physics, such as gravity, electro-magnetism, quantum physics, thermo dynamics etc., were very different, I assume there would be no structure i.e. no matter at all. Meaning that according to my suspicion any simulation would result in a very, very similar world to the original. Meaning it wouldn't matter whether we are a simulation or not.

References: Wolfram, A new kind of Science; Chown, Never ending days of being dead; Dogaru & Chua, Edge of chaos and local activity domain of FitzHugh-nagumo