some launch option's for play good L4D2

-Heapsize 2097152
-threads 4
-nod3d9ex
-16bpp
-noaafonts
-novid:** This option skips the Valve introductory video.
-console:** This option opens the console in-game.
-nopreload:** This option prevents the game from preloading all of the assets, which can improve loading times.
-high:** This option sets the priority of the game to "high", which can improve performance.
-threads X:** This option sets the number of threads that the game uses. The default is 4, but you can increase it to improve performance if your CPU has more than 4 cores.
-dxlevel 81:** This option forces the game to use DirectX 8.1, which can improve performance on older systems.
-refresh 144:** This option sets the refresh rate of the game to 144Hz, which can improve smoothness if your monitor supports it.
-mat_queue_mode 2:** This option improves the performance of the game's physics.
-cl_disablehtmlmotd 1:** This option prevents the game from displaying the HTML MOTD, which can improve loading times.