Also, Naughty Dog's games do _not_ use Lisp, they use a custom language that looks a little like Lisp, but has no garbage collector.
An example was Thinlisp, which tries to be mostly compatible with Common Lisp, but without GC. The compiler for Thinlisp is written in Common Lisp.
G2's Gensym is written in such a Lisp. Thinlisp also comes from them, IIRC. http://www.gensym.com
Some Lisp don't/didn't use a GC, but reference counting or similar schemes.
Also, Naughty Dog's games do _not_ use Lisp, they use a custom language that looks a little like Lisp, but has no garbage collector.