You can play the complete games thanks to the Internet Archive:
You can increase the mouse sensivity and the screen size to the maximum value for a better confort.
Use the left mouse button to shoot, and the middle mouse button to open doors.
You can use both keyboard arrow keys and mouse together for faster movements.
Spear of Destiny
Sames controls than for Wolf3D.
Play the 2nd and 3rd missions to get the new sounds and graphics from FormGen.
You can also the shareware versions of the games:
You can buy and download the full version of Wolfenstein 3D and Spear of Destiny on Steam, either alone, or within the Wolf pack also containing Return to Castle Wolfenstein. This is the recommanded way to get a full version of these games that is compatible with the latest 32 and 64-bits operating systems (with preinstalled DOSBox).
Currrently, you can also (try to) play to the first 3 missions of Wolfenstein 3D on your (HTML5 compatible) web browser on the official website of the series.