From IMDB:
Effects, and Sound Effects changed in the 25th Anniversary Edition:
- While Ripley is contacting traffic control now, the last shot of the Nostromo in space now has a star field where there was just a Black Background.
- The Alien Transmission and the keyboard button sound effects are much different from the original deleted scene.
- The shot of the Nostromo rolling 92 degrees to port now features a star field to the left of the planet where there was just black.
- When parker gets drenched in Brett's blood, the sound effects of the cattle prod hitting the ground is different the original deleted scene.
- When Ripley tries to contact Lambert and Parker through the coms after leaving Mother's chamber, static can be heard when she tries a different channel.
Those two tweaks were the ones I was talking about earlier... it would be nice if you could check it for me, dark_jedi. Thanks.