It started lagging for me pretty hard after alt-tabbing in and out of the browser (firefox), after some time it "fixed" itself but then after a couple seconds randomly made the whole browser white? Then it got "fixed" again, but the game crashed and returned a "NS_ERROR_OUT_OF_MEMORY" message (which is unlikely, I had a couple GB of ram and vram free). this issue somehow didn't happen on older versions of the game.
Would also be nice if you could play it with WASD