Dickinson doesn't go too crazy with the sound games in this one, but she still plays a few. In the first stanza, for example, we get a bit of consonance with the repetition of the K sound in words like "Blank," "Mechanic," and "Alike":
From Blank to Blank—
A Threadless Way
I pushed Mechanic feet—
To stop—or perish—or advance—
It's interesting that she'd choose to repeat a sound with such a sharp edge when the speaker is wandering through a world of mushy formlessness. Do the sharp K sounds somehow represent the speaker puncturing this mushy world as she wanders through it? Is the speaker the proverbial fork in the mashed potatoes? (Wait, there's actually no proverb about a fork in the mashed potatoes...)
In any case, the second stanza has some cool stuff going on as well. For one, we've got more consonance, with repeated D sounds in "end," "gained," "beyond," "indefinite," and "disclosed." We also have some assonance, with short I sounds in "If," "It," "indefinite," and "disclosed":
If end I gained
It ends beyond
Check out how each of these lines begin with a short I sound, but then the next line has a long I: "I shut my eyes—and groped as well"
(9). The three short I sounds in a row give us a closed-off feeling. It's almost like the speaker is feeling more and more frantic and caged by all this nothingness, but then the long I comes along with a much more open sound. It's sort of like the speaker breathes a small sigh of relief as she closes her eyes. Dickinson then uses assonance to continue the long I sound into the last line: "'Twas lighter—to be Blind—" (10).
So we end in a slightly more open place sonically, which is kind of ironic since the speaker is closing her eyes. That openness does relate to the poem's final line, however, which finds some kind of comfort in keeping those peepers shut.