Thanks for taking the time to play my submission!
Another user also had trouble with keyboard input. I believe it has something to due with the way itch.io embeds the page in an iframe, as a local browser page with the application *seems* to handle keystrokes fine. A copy of the game without the aforementioned issue can be found on my personal site at https://www.ashn.dev/proj/life.html as an FYI to anyone else reading this comment.
Additionally, running:
$ make life.bundle.html
from within the source directory should build the non-native version of the application as seen on itch.io (requires emcc in your $PATH). Building this make target should avoid all the hassle of needing to manually set make environment variables. The make targets have only been tested on a Debian-based OS but they *might* work out of the box on OSX.
Anyway thanks again for taking the time to play my submission. This was my first-ever jam so I appreciate any and all feedback.