are there any other languages that support for example lisp-like interactive REPL, eg analyzing program state while it is running?
Conveniently analysing program state while it's running is more a feature of languages that run in an image than something lisplikes have in common, like Common Lisp, Factor and Pharo, but not Racket or Guile.
There's atoms, and lists, and at the highest level of a program, the head of the list is the thing to be invoked (function, macro, special form) and the tail is a list of args. At lower levels, the higher level context says what a list means, but either a list itself or the same head/tail interpretation are the main things.
And there are some quoting constructs that control if things are bare atoms or references to the values of names, etc., and that's about it. Lisp has very little syntax. I mean, unless your main language is raw assembler or some esoteric toy like brainfuck, lisp almost certainly has much less syntax.
> are there any other languages that support for example lisp-like interactive REPL, eg analyzing program state while it is running?
Erlang.
Ruby (via Pry).
Lots of others.
Umm, do you know any language with simpler syntax than Lisp has?
For me, the main problem with Lisp is that there's so many Lisps. I think I philosophically prefer Scheme over Common Lisp, but then again there are so many Schemes to choose from!