All of the bugs and limitations are 100% Zak Fenton's fault.
However, he isn't entirely to blame for all of the good parts.
The core virtual machine is a modernised version of Public Domain Smalltalk, which was based on (or a clone of) Little Smalltalk, which in turn was a (more portable) clone of Smalltalk.
The changes and extensions I've made on top have mostly been inspired by other projects like SQLite, Lua, Duktape and Gtk.
If you prefer, you can just blame Microsoft for the whole thing - they're the ones who taught me BASIC and convinced me to switch to Linux.
So instead of just giving you a list of credits, I'll let you search for these things online.