I run ArchLinux and downloaded the 64-bit version of the game today. I attempted to play it but hit the Data/Audio/Sounds/Languages issue with the update it applied, and worked around it with a symlink to Data/Core/Languages. Aside from that, here's my impressions:
Initial impressions (launcher):
Launcher worked straight away with no issues (using Linux x64 ./Pandora). Update was found, noticed the launcher interface was clean and well presented.
Update applied fine, launcher restarted and checked for update again - thankfully didn't take too long, so I didn't mind.
It then tried to go fullscreen and launch the game. Seemed like it was about to come up, and then crashed (due to issue explained above)
Worked around it, and things went fine from there.
Initial impressions (game):
* Clean main menu interface
* Seeing the different faction choices in the 'New Game' section made me realise there'll be a lot of reading to go through in this game and a bit of familiarisation to understand what all the different modifiers really mean.
* Wasn't expecting a cutscene, though it looked nice, but also seemed like there wasn't enough to it.
* Finally in-game. I realise the tips aren't always in sync with what you're doing/what you're up to.
* I accidentally hit 'Disband' at one point and no confirmation came up, it just disbanded an early troop!. This seemed like a pretty bad thing when you're a new player and aren't familiar with the interface just yet. If you take anything from this, please consider at least making this confirm your disband choice!
* Research confused me. On first turn it said to choose research, and I thought all the blackish coloured buttons meant they were not a choosable research option! I thought I had selected the blue research option that was actually already researched! Didn't realise this until turn 3! Make the avialable research options stand out a little more.
* Encountering lots of monsters pretty early. Fair enough, wasn't expecting so many so quickly but could make things interesting, and I did notice it was a configurable option when setting up the game.
* I love the 'Report' windows on various discoveries etc, with the various quotes before a report. Nice touch!
* Found myself getting around the interface pretty quickly. Right click for moving, left click on city name to open the city, seems intuitive.
* I find the micromanagement of human resources in a colony a bit unexplained from the tips that came up though. How am I supposed to know what's good for a starting colony vs. what's good for a mid/large colony? A little more explanation might be nice?
* I noticed a spelling mistake in a response when I first encountered another faction on the map. I can't remember the full sentence sorry, but I remember the word 'already' was spelt 'alreayd' . I was the scientific faction and I _think_ it just met the militaristic faction based on how they greeted me. Hope this is enough for you to find it.
All in all, a good experience. I did stop playing about 20-30 mins in though as it's late. I can see this game being very easy to keep playing "just another turn", and it's already reasonably polished for a beta, but I do feel you should be doing some major playtesting and final polish right now just to give it that little bit more before release! Looks like a game I'll be buying!!
Oh BTW, I was playing on my secondary PC which only has a Geforce GT8800, and a Core2 Duo E8500. The game was a little choppy when zoomed out on the map with the default settings it was configured with. I don't know if you auto-detect appropriate settings for the environment, but if you do, you might want to lower them slightly for this setup.
Also, thank you so much for the Linux support. Great to be seeing a Linux client in your beta list