The 22-man team working to modernize Goldeneye 64 with the Source Engine have given everyone the perfect Christmas gift: a public beta showing off the fruits of their labor. (It's just a step above last year's present, the alpha version.)
The mod, which requires a Source-based game to work, has already garnered much attention over the years for the level of detail in its stage design and weaponry. All information, including known bugs, can be found on the developer Wiki. Here are some suggestions, via the mod's main website, on how to stabilize the game:
Check for and download latest video card drivers
A server with 10 people seems to work better
Have the Base SDK installed
Download the mod again on another mirror and reinstall the mod.
Turn HDR off
Turn shadow detail on low
A patch is being planned but no date has been determined.