Is this grammatical?

I'm sitting in an old wooden rocking chair. My hands and feet are bound together and tied to the chair, and my mouth is covered with black masking tape. Ahead of me is a laced wooden window, outside which lies dense pine forests. Where am I, I ask myself?
I hear the noise of footsteps creeping up behind me. I can't see who or what is making the footsteps, but I smell a strong cologne. The footsteps crescendo. Who is it? Please don't hurt me, I cry.
Ah. David. You made it!
I hear the voice of an elderly woman. I try to discern her accent.
It is time, David. Time to do the job you were designed to do.
Job? What Job? Where am I, who are you, how did I get here? Just some of the many questions I'm thinking anxiously.
I calm myself down and become rational in my thinking. Her accent. Is it Russian, no. German, no. Possibly Scandinavian! I think. And given the interior design of the house, the pine forests outside, I conclude that I’m somewhere in Scandinavia. Whether it's Sweden, Norway, or Denmark, I don't know. As for how I got here, I don't know that too. But I do know that I'm in danger, and must free myself because I've a feeling that this place may become my tomb.
I’ve been waiting many years for this day, David. You don't understand how important you are to me, to us, to the survival of the human race.
Long and thin fingers come over my face, and pull the masking tape away from my mouth. Ouch! Part of my lip comes away with it, and blood runs down my chin. I'd never seen fingers as long as hers; they are alien like.
Show yourself! Why are you hiding behind me? I cry.
The genetic experiments failed, David. The human race mutated uncontrollably to its death. I'm the last human left in this world. I didn't take the pills like everyone else. Thanks to my father, the late Dr Wilson, I was skeptical of this new science, of gene therapy, of how pills could change your body. They say the pills cause mutations in your DNA, at a cellular level. I only got to the first stages of mutation. My mind remains unscathed, even if my limbs are a little longer perhaps.

Is this all grammatical? Thanks!