It had largely Lisp-like semantics and Algol 60-like syntax.
Today it is mostly remembered for its syntax, but in fact it had many features beyond those of early Lisps.
Its use of fully parenthesized notation was also considered a problem.
[1] Lisp 2 was a joint project of the System Development Corporation and Information International, Inc., and was intended for the IBM built AN/FSQ-32 military computer.
Development later shifted to the IBM 360/67 and the Digital Equipment Corporation PDP-6.