It is deﬁnitely not browser-based but if you want to check which OpenType Layout features are present in a CFF or TTF font, the free light version of DTL OTMaster (macOS, Windows, Linux) might be useful. The full OTM version (an absolute bargain for €255) also opens WOFF(2).
Talking about IKARUS: in 2013 together with Adobe I published Digital Typography & Artificial Intelligence in the context of the Dr. Peter Karow Award for Font Technology & Digital Typography. This award is presented once per ﬁve years to a person who makes an exceptional and innovative contribution to the development of digital type and typography related technology. In 2013 the PKA was presented to Dr. Donald E. Knuth .
Preparations for the PKA 2018 have started and therefore Digital Typography & Artificial Intelligence is available as PDF now.
Drawing by hand, at least when it is small, doesn't offer the crisp lines that digital design does, so it is more difficult to add subtle details like corners in curves and that stuff.
I think that this purely relies on the drawing skills of the type designer. The cover below is from a publication by Gerrit Noordzij on type designs by Dutch art-school students that dates from 1983. The size of the booklet is A4 and Gerrit used my letters 1:1 for the cover. These letters were made completely freehand, except for the straight lines.
And, of course, Gerrit Noordzij’s own type designs, which he applied on book jackets, were made by hand: he used brush and paint on polyester ﬁlm. I think these letters are pretty subtle and crisp.