I think we were just both killed by asteroids the first time (just starting to learn the controls) - but instead of respawning the asteroid movements and music went on - but without any message or action - similar to a screensaver - so I killed the process from text terminal. Maybe I missed something ...
I think we than tried team mode but were not able to be both in one party - we will look into it when we meet again to play and look for "arcade mode".
Personally I am a fan of casual games - small fascinating games which one nearly can play in seconds - especially when local coop mode is supported for 2 and more players. And I really miss those classical pacman, snake, asteroids, ... games using current HW. There were no shortage of such games under DOS ... but today games are mostly made to be played for days or weeks - which is too much for my taste. I others shout that a game is too short (but otherwise good - it typically suits me. ;)