It was an interesting plot, but I thought that this kind of story requires a bit more dialogues to build the tension and make it more interesting. Apart from this, I found it difficult to follow in places because of some confusing sentences. The flow was choppy, and the switching of tenses, was all over. Apart from the flash back bit, you have to stay either present or past, which I’ll leave it to you, since there are too many of these. I’m sure when you give it a careful read you’ll figure it out. I will point out some sentences you need to rephrase.
His hoarse voice growled, sounds a little cliché. You may want to replace ‘growled‘, or say something like; his hoarse voice ripped through my ears for the first time.
I heard that it felt nice though, a sort of intoxicating feeling the first time. I needed to feel intoxicated. I needed to feel anything but fear and pain.
You may want to rephrase this; I heard it made you feel intoxicated the first time, and I was desperate to feel anything but fear and pain.
Also I think you’ve to change the paragraph when starting the flash back (It happened last night…)
Page 1, last paragraph: My tongue felt like a vile ash had settled on it : my tongue felt as if a vile ash had settled on it.
His eyes examine me coldly. His eyes are hollow, like black pits of tar. You can rephrase this in one sentence: His hollow eyes like black pits of tar, examine me coldly.
This is an awkward sentence
He doesn’t laugh like I think other people would. - He won’t laugh like others normally would. Sounds much better.
Once the cigarette has burnt to the filter my head begins to spin a little. I feel as though I am no longer grounded, no longer tied…
How about; Once the cigarette has burnt to the filter, my head begins to spin, making me feel no longer grounded or tied to the chair.
He was already shoving sticky tape over my mouth - ‘shoving’ I think is a verb which indicates forcing something inside. So, here, you either simply say ‘sticking a tape’ or 'using a sticky tape to shut my mouth.'
Page 2 second paragraph: You wrote ‘maybe nobody will ever realize I was missing‘. You’ve already said ‘and I didn’t know by now if anyone would even know I was missing’ which says the same thing, so no need to repeat it.
We already know that she’s tied up in the cellar, so you don’t need to mention “cellar door” or “damp cellar”
The thuds on the stairs mark his return (I like this, by the way - it made my heart beat faster) to the damp cellar. His presence instantly chills me. His face is so blank so unreadable. - You can pile these up to a neat little sentence:
The thuds on the stairs mark his return, chillingly making me aware of his presence with his blank unreadable face.
Page 2 second paragraph I would’ve started like this;
I hear a doorbell above, and try to scream but he was already shutting my mouth with a sticky tape. He races upstairs and firmly slams the door shut. I have no idea if it is a day or a night or if anyone will notice my absence by now.
The sentence in this paragraph that begins “I always thought people who abducted others…” until “a woman tied to a chair in his cellar” seems incomplete.
How about this: Unlike my abductor, I thought kidnappers were mostly irrational, overtly emotional and psychopathic people. He does however have some traits of a psychopath - he is quiet, mysterious ( I would’ve used sinister rather than mysterious ), possesses a gun and has a woman tied up in his cellar.
He lit another cigarette and I wondered how many times we would have o go through me smoking, him smoking, me smoking him smoking….- This is a very untidy sentence. You’ve got to rephrase this. A suggestion :
I wonder if he’s going to let me have a drag again.
I think after you iron all these out, this could turn out to be a very promising story. I hope I did not get carried away with my corrections, and hope this was useful.