I've been playing Nexuiz for a few weeks now, and I think its great. Before I forget what it was like to be new I'd like to share some (hopefully) helpful feedback on what was confusing for me when I first started.
While Nexuiz is loading it displays the Nexuiz symbol, then the Alien Trap logo and finally, once it is loaded, the user is presented with a blank screen with menu options at the top and a few buttons at the bottom.
I started by clicking on "Instant Action", which worked, but I then became curious - What is the difference between "Instant Action" and "Campaign"? Are they different game modes? What about "Create"? Is that a different game mode? Although I later figured this out, and I'm sure its documented somewhere, I want to suggest how you could make it easier to understand for new users.
You could have something like bubble help for each of the buttons, but I don't know if that is easy with Nexuiz's custom GUI. What might be easy is putting a little bit of help text on the background of the otherwise blank portion of the screen. Something like:
Campaign - Start here and work your way through various maps by playing against bots.
Instant Action - Replay a random campaign that you've already played.
Join - Play against other humans online.
Create - Create new map modes to play against other humans online.
Options - Configure everything from the way your avatar looks, to the music, to the keybindings, etc.
Quit - Exit Nexuiz.
Sometimes people make hasty judgments about games (They download it and try it without reading anything. And they may falsely think it sucks and stop playing it). The above would immediately convey "This game let's you play offline with bots, online with people and the game modes are flexible. It's also highly configurable."
The other area that could be made easier is mapping. I hesitate to bring this up since it appears from this thread:
http://www.alientrap.org/forum/viewtopic.php?t=10
that people are actively working on making gtkradiant work better with Nexuiz. But there is a lot of different posts and information to sort through. Something like a noob friendly hand holding tutorial that takes the mapper though configuring gtkradiant 1.5 for Nexuiz 2.0 (if need be) and that includes the resulting *.map files for the user to download and look at would be great. Perhaps Docs/mapping.txt could be renamed to something like Docs/mapscripts.txt and Docs/mapping.txt could be a quick overview of how to get started with gtkradiant, even if it is just a copy of the most helpful posts in the above URL.
Anyway, thanks for making such a great game. I just wanted to give my $0.02 on things that might make it easier for new users.