Very solid retro shooter. Performance was good for me, even on webgl. The soundtrack is a great fit and really helps to sell the retro feel as well. The lack of a death animation was jarring but also contributes to the retro feel I suppose. The only real issue I had was that you would get shot the second a door opened often without having a chance to react, and at one point on level, 3 I think?, I had someone actually shoot me through the wall as soon as I opened a door. But otherwise, fun game and you really nailed the look and feel of a classic fps like Doom.