Westerns are notoriously hit-or-miss when it comes to critical reception, but over the decades several have been able to achieve the coveted 100% rating on the review aggregator site Rotten Tomatoes. On Rotten Tomatoes, a film can be either "fresh" or "rotten", and the metric operates almost like a pass/fail, with very little nuance to an individual critic's score. A 100% rating on Rotten Tomatoes indicates that all critics who reviewed the film put it on the positive side of the scale – it is not necessarily an indicator that the film is near-perfect.

https://screenrant.com/western-movies-100-percent-rotten-tomatoes/