Descent: Crap. Not smelly crap, but nothing that I haven't seen in my 80's Tunnels games.
Doom: Ultracrap
Java/Shockwave: Crap to the nth power.
I may be more critical than some, but I have found that if you know what you want, you can find long-dead or obscure games that give you exactly that- not much else, but generally exactly what matters to you. Everything else, particularly such pathetic special-effects shows as Doom (no content or much else, and of course now- ever see an old Flash Gordon? I rest my case. I could go on about this for days, you know- I spent years trying to find a set of games that required neural impuses AND were any good, and have come upon everything I personally will need for the next 20 years- all either abandonware or hard to find as the devil.