[4] The game's controls are less "floaty" than those of the original and feature new abilities such as wall jumping and grabbing onto ledges, being more in line with the gameplay the series has employed since Super Metroid.

[13] The scale of the rooms throughout the game world also had to be changed, with some landmarks being redesigned to make better use of the larger screen; some, however, were kept similar in size to their Metroid II counterparts.

[13] This, along with increasingly darker and menacing music, was to recreate the feeling of Metroid II, which Guasti described as "being lost in a dark, mysterious cave without knowing what's ahead".

[10] In late 2014, the project was ported to the newer version of GameMaker Studio, which enabled improved loading times and performance, but required the complete rewriting of some features and changes to the designs of some levels.

This move also made bugs faster to fix and new builds easier to make, leaving the development progress in a more expedient and productive state.

[3][17] Updated versions with further improvements and features were planned, but shortly after the first release, Nintendo sent DMCA notices to websites hosting it.

[25] Other members of the AM2R team formed SquidShock Studios and began work on an original Metroidvania, Bō: Path of the Teal Lotus, using hand-drawn art and inspired by games like Hollow Knight and Okami.

[26] Mike Fahey, writing for Kotaku, called the game brilliant and compared the gameplay, graphics, and music favorably to their Metroid II counterparts.

[9] Tom Sykes at PC Gamer praised AM2R as a "great game in its own right" regardless of whether one had played Metroid II prior or not.

[29] NF Magazine's Tony Ponce initially worried that the game would lose the "eerie charm" of Metroid II, but found it to be able to keep a high-tension feeling, as well as including new things for longtime fans of the original.

[8] Furniss found that the gameplay changes compared to the original Metroid II, such as the ability to grab onto ledges, all felt natural, and called the user interface "sleek".

[27] Ponce found the precise win conditions for Metroid battles annoying considering how often they are fought, but similarly thought that the new non-Metroid bosses were among the most exciting and challenging in all 2D games in the series.

[30] Jeffrey Matulef, writing for Eurogamer, found it impressive how closely the game resembled Super Metroid visually.

The Game Awards host Geoff Keighley explained that AM2R and Pokémon Uranium were not legally cleared by Nintendo to be included in the event.