You're right, 10.04 works fine as far as audio crackle issues, except it takes a super long time for the loading screen to pass for some reason and failed to output audio over digital optical for some reason even though normal digital worked.
All-in-all a fairly good Linux game attempt but marred by the fact that it's a) increadibly hard even on easy due to lack of money and high expenses for sone thing, which isn't helped by the fact that replaying older missions give you 1/2 the money, so you're penalized even further for not doing well b) a kinda cool concept to have three different flight layers, but seems to mostly only serve to make things confusing and that, combined with the fact that asteroids are black against a dark background, makes level 5 nearly impossible, or impossible to complete well at least.