I actually have to disagree and say playable. It probably depends on your cpu strength but I maintained 60 most of the time. One thing to note about fps is the shader compilation in this game is killer, so expect to struggle with that on a first pass. The game has frameskip it seems so if you're above 30 fps it still feels relatively smooth, no slowdown. But if you're compiling while getting shot at... Not much can be done about that.
Sound was perfect, graphics were perfect or close to (a couple very far objects seemed to have its shadows flicker sometimes. Can't tell if emulator or game's fault).
I played multiple levels with no issue.