It seems I've gotten all the artifacts for the moment!
I tried playing the browser version first, but it kept freezing up if I switched while an enemy was firing (or something, I'm not entirely sure what the issue was.) The downloadable version worked perfectly fine.
I like the idea, I think it's well executed. However there are two very enclosed areas where you must be the same frequency as the guard in order to activate a button where I found it next to impossible to avoid taking damage. I might be missing a trick on how to do that section.
Other than that, everything works great!