There is zero rebound when it lands, that's a bit weird. I replayed that part a couple of times, it doesn't look like there is any vertical velocity at all when it lands, which, given SpaceX's ability to do this with much heavier objects should be no surprise but it makes it look as if the vehicle has very little mass. If the tanks contain 250Kg of compressed air (which means it is pretty much liquid) and you toss that out in ~1 second or so then you'll be near the end of the depletion so if the vehicle would be launched just a little bit higher it would slam into the ground instead of gently landing. There isn't much reserve there.
er, but it's also being propelled. Maybe they are able to ease off the thrusters so it's a soft landing.
I do think that this could only work for a short timespan and getting it to work perfectly each time with variances in weight would be hard. I'd imagine the thrusters and the tank would would wear out over time too, would be a nasty landing if only some of the thrusters worked.