Developmental editing is fixing or developing the high-level stuff in a manuscript; story, plot, genre, character development, really all of the big picture stuff that makes a manuscript "work." What you'll get here is detailed page-by-page in-text comments about the various elements that I see that could be improved upon and full-text report of at least one page that gives a narrative feedback on how the story works (or doesn't) and how I think your time would be best spent to make it market-ready. I'll also comment on and fix glaring style, grammar, etc. issues that I notice, but the story will be my main focus.
I can also do a manuscript assessment for $1/page as well. An assessment is like a dev edit, but it will be significantly less detailed in feedback. I might throw some in-text comments if it seems appropriate, but the primary deliverable will be a 2-5 page narrative feedback document in which I'll give my frank assessment of the strengths and weaknesses of the manuscript, it's viability in the market*, and a recommendation of how to proceed. Basically, I'll be giving you the low down on how to make the manuscript better, and you'll do the fixing yourself.