Last stroke of /M/m/n/ could dip below the baseline a bit so it doesn't look like it is riding high. The rounded bowls of /B/P/R/ don't seem to me to fit the style of the design, and similarly /S/s/ may be too smooth. /b/d/p/q/ are too wide. Serifs at top left of /E/F/ should be more substantial. I think the nearly monoline light weight loses a lot of what makes the design appealing.
That /o/ looks happier. The /v/ really brings out what Tom said--your overshoots are insufficient. It looks like it goes up further than /n/ and /i/. Should /v/'s serifs be unbracketed like /H/'s? I do think, as Nathan said, the cap serifs should be more substantial than the lowercase.
/o/ looks light. Since a curve is only at its thickest for a moment (vs. a straight stem which stays thick), its width needs to be boosted to optically match. The /o/ (particularly the outer contour) seems a little lumpy to my eye. /n/ shoulder too--curves are hard! Do you have more nodes than necessary along those contours?
I think if the head serifs are all sharp corners, the baseline serifs shouldn't have those rounded tops.