Yeah the app let's you pick how long and how often you'd like the train. As little as 15 min and I think up to 45 or 60 min. With the warm-up, the shortest takes maybe 20 min. Nice for a deload, active recovery, or even part of a more fleshed out session that includes kettlebells.
They are working on new rings programming, but in the meantime, if you can track down some of their older rings stuff (if that is on your list of goals at all), I highly recommend it. I did maybe 6 months of rings training + S&S style swing progression, and some Elements on odd days, and loved it. Talk about WTH effect. PR'ed my TGU without training it.