I like the |R| and curvature of the |S|. That being said, compared to the rest of the letters, |S| is definitely too narrow...
|M| and |N| seem same width - I assume that's intended, but would it loose anything if the |N| was a bit narrower?
Legibility will be an issue with such chunks of letterforms being cut out. I see no apparent problems with most of the letters, but I think |O| is confusing and the |Q| is totally wrong (it doesn't look like letter Q at all, those two glyphs (|O| and |Q|) if placed alone on a sheet of paper, wouldn't be recognized as letters I'm affraid). I assume you try to avoid any descenders, that's why you made |Q|'s tail fit close to the baseline and thus making the main part of this letter smaller than the |O|, but it may look awkward.
Try to find a way to justify the size of the gaps, look for example at the |X| or |Z| - why are the gaps different there?

Actually I think the Q works quite well. The O is a bit off though, could be a tilted U.

Is there going to be a lower case?

Something interesting here. I would work on the gap between some letters. The one on rounded one are too short (R,P) compare to the one on the stems (W,D). To me the I seems an underscore T and the Q is a bit too small. Keep going.