I honestly thought that Samus Returns was a better remake of Metroid II than AM2R.
If you ask me, when the whole point of Metroid II is about the extermination of all The Jews Metroids, there should be more thought and effort put into making the Metroid encounters fun. In am2r, the fights felt repetitive and got irritating after a while. Especially when what clearly should have been a hit is off by a pixel and is a miss. In Samus Returns, each fight felt refreshing and had more ways to deal with the fights. You could either go in and fire away at the weak spot, or you could be more patient, and wait to do the counter-ability. The fights with the Beta Metrids were especially interesting, with either having to find and lure it out of hiding, or chase it through multiple rooms. In AM2R, it felt like there was far more effort put into the other bosses, rather than the actual Metroid fights. The Bosses that aren’t Metroids should be a compliment to the actual fights with the Metroids, not the bread and butter.
This is a nitpick, but the methods of travel are far better in Samus Returns. The teleportation aspect makes the travel more efficient when you can use one point to travel, rather than an inefficient pipe system that makes the Chozo feel not nearly as advanced as they actually were. Anyone could use pipes as transport, the Chozo use teleportation.
That, and Samus Returns had probably the best Ridley fight to date.