This book felt like a first effort to me. The concept is intriguing, but the delivery seemed disjointed. Many times I found myself in long descriptive passages, wondering when the plot would advance ... or where the plot was, frankly. Then all of a sudden, in a few paragraphs, the plot would jerk forward with little explication. This would be followed by more lush descriptive passages which had little or nothing to do with moving the plot forward...
An example of the plot vagueness: several times we are reminded that Gonzales' memex (HeyMex) is in some way colluding with Aleph to do ... something. We never learn what. At one point HeyMex wishes it could talk with Gonzales, and goes to some effort to find him. But when they finally do meet, they exchange two sentences of dialog.
Another example: near then end, two characters fall in (love? lust?) and are married. But there is very little intercharacter development on which to base their sudden marriage.
I think there may be a good book in here, somewhere. But it needs more editorial and authorial work to bring it out.
An excellent read, Lovecraft is truly a master of his craft. This is my favorite Lovecraft novella so far.