Funtauna is a still unfinished slab serif with rectangular joints:

There are no kerning tables yet, but I consider the general spacing as more or less done.
Later, I will add also a light face and oblique faces. The x-height and the average gray value fit Palatino.
Any suggestions (except kerning) are welcome (glyph shapes, proportions, rhythm, details, spacing, accents, ...).
Comments
Kerning and spacing are nearly finished now:
To me it looks okay but not yet convincing. There are a couple of glyphs that are difficult, like the "t" or the "f". Combinations like "lt" or "ji" have too big gaps inbetween.
Are you really doing this in METAFONT? Impressive if so.
The monospace has progressed, too (look at the m,i,j,J,t):
Floating text in monospace:
Ragged right:
(as an accompaniment to a traditional body text typeface such as Palatino).
Source codes may include short commentary paragraphs. Therefore, my tests with Funtauna always include a test as body text font (but personally I would not use Funtauna in a book as body text font). So Funtauna is neither a display font nor a body font. However, I will provide some faces, that are intended as display fonts:
And:
I have increased the width of the s and decreased the widths of p, q, d, g:
Which glpyhs of the mono look clipped along the baseline? The round ones (like o)?
I find the round corners too bold and unbalanced. Maybe you can solve the problem, if you draw the corner connections more round. Difficult for me to explain, so I made a quick sketch.
It's not perfectly and a bit over the top, but I hope it shows you what I mean.
For the ß, I would suggest clipping the right serif of the left stem to allow the gap in the bottom to be more prominent. I also think the bottom-heavy distribution of counters is favorable.
BTW, I'm assuming the name is Rumantsch, so it should be pronounced [fun'tɛ:mɐ]?
I cannot increase the global roundness, because otherwise letters like h or n would look a bit vertically skewed in small sizes (due to the rectangular join).
Should I make the round corner parts even thinner?