Really nice game. I like the muted colors for the background and most of the sprites. Together with the music it gives a nice somber athmosphere, which sets it apart from other similar games. I also like the random shapes that 'float' around. Makes me wonder if there is something else going on here :D
I think item placement could be improves. I spend a really long time not having any ammo. But then again, I didn't die, even after I reached zero health.
Anyway, good job.
(It ran fine in the browser for me, but I had also issues with the web export on slower machines)