This might be of interest:
http://www.samsdotpublishing.com/tentacles.htm
The imminent death cheapens your ending and the recorder is kind of hackneyed at this point. The atmosphere and usage are skillfully vintage and ring true. I think you may actually have a better story with a survivor than with a casualty. I'm not saying turn the narrator into some howling Friday the 13th style wildman proclaiming dark prophecies, but your ending would feel harsher if he walked away from it.