Some Critiques
I apologize if this seems a bit harsh. In truth, I believe this poem has potential but needs some minor edits as well as some larger thematic issues (har har, like we haven't heard that before).
Towers surround me on every corner.
I fail to see the relation of this line to the rest of the poem. It would be nice if it correlated a little. As is, "towers" has little meaning and no meaning is established within the line, other than the fact that they "surround" the speaker. This alone could mean one of many things, but is left too ambiguous to have any true significance. Why "towers" instead of any other object?
I understand that the assignment forced you into using the word this way, but there could be more innovative ways to use it.
Looking through iron bars,
I see those that infest this hole,
It's like a sea of grey.
Transition from the penultimate to the final line is bad (sentence splice). Introduce a semicolon or reword the last line. "It's" is currently too ambiguous - is it the scene that is like a "sea of grey"? The hole? Some unrelated object?
I like the idiosyncratic use of "grey" to describe the being of the "sea." You could go further with this idea.
I would also complain about using the word "see," but the synergy with its homophone in the next line gives me <3.
The stink of blood fills my cell.
Evil ideas seem to propogate in my head.
Typo @ propagate.
This is okay - perhaps consider rewording "evil ideas" for emphasis.
This place is hell, the devils domain.
Typo @ Hell / Devil's; capitalize proper names.
I think "the Devil's domain" is a bit excessive. By saying only "Hell," the line gains unsaid strength that would otherwise be lost in the longer form.
You could be inventive with the word "place." As it stands, it sounds quite passive and lackluster, but words like "crucible" could draw a negative connotation. You could even stretch it to words like "furnace" to emphasize the suffocating environment. Even "domicile," while not strictly negative, could give a sense of overwhelming the reader even by how it sounds.
I lay on a spongy floor,
With an itch I cannot reach,
For my arms are binded tight.
"Binded" should be "bound."
"Lay" should be "lie" to follow the trend of present tense.
"Spongy" seems out of place and/or forced. At first I thought it was a word you had to use, but it's not on the list.
Consider something like "end" "extinguish" for "reach."
We're treated like dirt.
It sounds out of place.
The poison that we call reality,
Surrounds us in this hole.
Omit "that" to pair the lines together in terms of beat. It will flow better.
The poison fills the place like a sewer.
I feel myself suffocating on this cloud.
I know my time has come.
Repetition of "the poison" seems unnecessary. The transition from the previous two more melodic lines is abrupt. We've already established that the poison is in a vessel in proximity to the speaker. In fact, "surrounds us in this hole" is much more effective than "fills the place like a sewer" since it introduces personal suffering and emphasizes the environment.
Is it supposed to be "in this cloud"? That seems to make more sense.