To beat Jetstream Sam on Revengeance difficulty in Metal Gear Rising: Revengeance, follow these detailed steps:

1. **Enter Ripper Mode**
– As soon as the battle with Jetstream Sam begins, enter Ripper Mode. This mode allows you to deal massive damage and break through his guard more easily.

2. **Rush and Break Guard**
– While in Ripper Mode, rush towards Sam. This will make it easier to break through his guard, allowing you to land critical hits.

3. **Perfect Parry**
– Instead of using Zandatsu, aim for a perfect parry. This will leave Sam vulnerable and set up for a quick finish.

4. **Finish with Two Hits**
– After a perfect parry, you should be able to finish Jetstream Sam with two hits. This method ensures that you avoid taking damage and achieve an S Rank.

Optional Techniques
– If you have access to Red Phosphorus Grenades, you can use them to temporarily blind Sam. This can give you an opportunity to get some attacks in before he recovers.

Additional Tips
– Ensure that you execute the combo correctly to maximize damage. A well-timed perfect parry followed by swift attacks will help you defeat Sam quickly and efficiently.
– As with any challenging fight, practice makes perfect. Familiarize yourself with Sam’s attack patterns and timing to improve your chances of success.

By following these steps and techniques, you should be able to beat Jetstream Sam on Revengeance difficulty without taking significant damage and achieve an S Rank.