scheme robots

A programming game I'm making
Any feedback is more than welcome
It runs in javascript and html5, and has a scheme interpreter that can't do proper tail recursion.
http://schemerobots.comlu.com/textarea.html
Put the code for each player in the textareas and press submit code.
Example code:
http://bpaste.net/show/hRqvv38dZSc3NtNNezaV/
It is a work in progress, creatures lose hp but don't die yet.

>>8
I'm not sure; I wouldn't have used environments for this in the first place.
There's also Gay Lisp, which is apparently r5rs-compliant. The home page suffers from Web 3.6 syndrome though.
http://gay-lisp.org/