Old vendettaer from 2004 here :) reinstalled the game today on both my android phone and Ubuntu 16.04 laptop. On the laptop, it seems my ship moves incontrollably, it's always reversing and moving to the left. I can, to a point, brake it using space. Happens both using laptop's keyboard and external keyboard.

Hello. As your device is a laptop, it is probably a fall sensor getting in the way. Linux treats it as an input device and Vendetta treats it like a joystick. See this thread https://www.vendetta-online.com/x/msgboard/6/30142

As well as blacklisting the device itself, you can also go onto Vendetta's joystick config page and if any Axis are shown, set them to "nothing" - this way VO will ignore any inputs that the device sends, and your keyboard and mouse should just work.