Part 1:
"You say he is working on an experiment" should be "You say you........"
Part 2:
"You stay away from the vehicles" should be "You step......."
If you speak to David just 1 time, then "Questions about the cell" will not be there, but if you then go to the garage, you will be able to select "You light the floor with the lamp" (that you have not got yet) and will get the message "The ground is dark, nothing can be seen" and get game over.
Part 3:
Same problem as in part 2 when restarting after dying.
You get info that "At dusk the moon shines" is the password. In the menu you can select this x2 times, but both answers will be wrong - you have to answer "At dusk shines the moon"
At some places "usas la pistola" and "pisas el acelerador" is not translated.