Oh it was perfectly playable even with the weird sounds and, as I said, these got fixed when I got to the next level.
The game usually runs ok, I use 800x600x32, textures set to 'best', no anisotropic filtering, particles set to 1.0, and the rest of the details to off, except for deluxe mapping and gloss. Usually there is no trouble with the framerate, as I get as much as I need for fluent gameplay (over 30fps).
The big problem is when I enter a game that has a lot of weapons or is crowded with a lot of stuff going on. It seems the pretty low RAM doesn't stand much of a chance and the system keeps using swap, causing those long long pauses at the beginning of the game that make me a very easy target

.