Companeros, if not a remake then definitely a sister film to The Mercenary, there are countless similarities between these two films.
They even begin their stories in the same manner, with a short scene followed by a long flashback for the rest of the film, until the very end when they catch up with the first scene.
It's one of the best spaghettis, no doubt about this, great cast, wonderful score, and so on. Many fans probably find it very entertaining among the Zapata SWs also, since it's more light-hearted and action-oriented than say Mercenary and Quien Sabe, while still having a certain depth.
But to me the script is a little weak, there really isn't much of any substance happening from the time Nero and Milian ride out to free Xantos until the time they come back to San Bernardino. A political western of this potential should have offered more I think.
One silly scene that really bothers me is also when John and his gang are waiting by the railway tracks. How the hell could a newspaper already be printed with the details of Yodlaf stealing the locomotive, and a short time later the engine appears with Yod on board. This is just downright stupid.
I also don't like the scene where Yod has a noose around his neck like Tuco, it doesn't work here and we've seen it before.
What saves Companeros is the whole final episode which is brilliant; Yod's raid on General Mongo's gang, the empty safe, Vasco and Lola marrying, the duel, last scene with Yod returning to the revolutionaries.
Top notch all of it, if the rest of the film had been on par it could have topped The Mercenary, as it is Companeros isn't even in my Top 20, while Mercenary is at #2.