retten is also used in the context of restoring or saving art pieces like paintings.
Can that be used for old cars as well?
Only in the context of them being historical pieces. Otherwise we would say "Wir restaurieren die Autos" just like in English "We restore the cars"
Is this under Science Fiction because in real life we are exterminating everything? T_T
Another sentence was about saving a dragon so that is probably where retten was inserted first and this is a secondary example thrown in.
Yes, it's a bit figurative, but works just as "saving" would in English in that case. You can't use "retten" for "saving something for later, saving money" - that would be "sparen".
It makes me a bit sad that Duo classifies this sentence as science-fiction
Is 'We rescue animals.' also a correct translation? or is there any special rule for Save v/s Rescue for retten
Yes, you are correct. This is another correct translation.
Just love this sentence. Wir sollen Tiere retten genau (just made up this sentence with my precarious German)
Don't destroy them and that is enough. They don't need you to help them.
Did anyone else write "we ride animals"? Easy mistake!