DOOM II on mobile! Original DOS version of DOOM II now have better mobile controls and very playable! Works great on Android and iPhone, you can try it here:
There is also Android version that have hardware acceleration in case if your device is not so powerful to play in browser:
This integration is powered by js-dos player. Use left stick for moving and to look around you can just swipe over screen.
In left side menu you can change sensitivity of mouse and size of mobile controls. Of course you can run it on PC too, controls are: WASD + Mouse.