>I gave it 5 stars because I use what I understand is the Roger Ebert style of rating

As I understand the Ebert system your review seems like a 3 star, that is to say if you like this kind of thing (hard sf, survival story in harsh environment using ingenuity) you will definitely like this example of it.

In 45 years as a reviewer Ebert gave nearly 1000 films 4 stars, I think about a 100 5 stars, although he was often thought of as being too lenient about a film's quality - https://www.rogerebert.com/roger-ebert/you-give-out-too-many...