You need to get used to the mouse handling for a bit, it's really old school but it's all there.
Should that be bits, not bytes? 256k bytes was massive in 1976. Even at 8 bits, that would be 16k. I don't know that much about Smalltalk, but that still seems like a lot of space for the era.
Looks like Alan Kay's baby is loaded with 96-512kb of memory. So it's not a challenge - but seems like an appropriate target.
Mind you the Alto was primo - Kay was prototyping the future using a wonderful resource called cash.
Granted this was a timeshare system, not a workstation, so that makes a huge difference.
Also I was talking with someone who wanted to implement a lisp for a microcontroller and we came to the conclusion that it had slightly less storage than the IBM that the original LISP was implemented on in the late 50s, which had a combination of drum and core.
If so, then $100K(1975) is $500K(2018).
Edit: I found a reference to the 1MB PDP-10 at MIT in 1979! https://www.filfre.net/2012/01/zil-and-the-z-machine/ mentions "Zork, a massive game that consumed 1 MB of memory on the PDP-10".
Alan Kay: "Actually, Bob Flegal's challenge was to somehow make a script font that kind of looked slanted but was actually straight up. I though he succeeded really well with this design." (http://lists.squeakfoundation.org/pipermail/squeak-dev/2004-...)
It was also the first system font used on the original Mac! (https://www.folklore.org/StoryView.py?project=Macintosh&stor...)
I also wonder about their choice of typeface though...