Just came across this – the entire Wolfenstein 3D (Chapters 1-3, there were 6 originally) which you can play in your browser.
The game is complete with the original sound effects and music, plus the levels and secret passages you may or may not have loved.
You can even keyboard map to keys you might have used back in the early 90s! No need for an Adlib or Sound Blaster card! I’m not sure if it supports PC speaker..
Don’t forget, there’s a secret passage at the end of Level 1 which takes you to Level 0 (or Level 10) for some serious score and extra lives. Go and re-live the classic!