I would first like to state that I have a profuse interest in video games. I have been a member of the Caves of Narshe forums, which is a Final Fantasy enthusiast's webite focusing on the S.N.E.S. and original Playstation games in the series, since 2004, and various claims regarding the legality of video game R.O.M. files and emulation have led me to want to do serious investigation research regarding the subject matter. Some of these included dubious claims regarding allowing copies for backup purposes of the sort that Nintendo is describing. Something along the lines of download only if you own the original game for backup purposes, or all downloads are offered for evaluation purposes only you must delete within 24 hours.
The first time I published my findings was in the Caves of Narshe Thread the Legality of R.O.Ms. in 2011, although I had not known about a couple of cases at that time. I also wrote something about it more recently on Academia S.E. in the related question Using downloaded N.E.S./S.N.E.S. R.O.M. Files for Research Work*. Unfortunately, this answer will probably not be much better than what I wrote at Academia, but perhaps I can do better.
The only backup provisions in U.S. statutory law are those described in U.S.C. Title 17 chapter §117. These are the only provisions in Chapter 1, which delimit the scope of copyright. No other statutory provisions exist in Chapter 1, which delimits the scope of copyright and lists the "limitations on exclusive rights" so granted. Moreover, there is no evaluation period so mentioned.
The provisions of §117 require an owner to make a copy pursuant to the following provisions in subsection (a):
Making of Additional Copy or Adaptation by Owner of Copy.—Notwithstanding the provisions of section 106, it is not an infringement for
the owner of a copy of a computer program to make or authorize the making of another copy or adaptation of that computer program provided:
(1) that such a new copy or adaptation is created as an essential step in the utilization of the computer program in conjunction with a machine and that it is used in no other manner, or
(2) that such new copy or adaptation is for archival purposes only and that all archival copies are destroyed in the event that continued possession of the computer program should cease to be rightful.
Subsection a1 allows you to do the bare minimum to actually use the software in your possession, and transferring it over the internet is not an essential step for using it. Subsection a2 allows the creation of a copy only to be used for personal backup purposes.
Neither of these exceptions account for the usage case of distributing §117 copy, which is handled under subsection (b):
Lease, Sale, or Other Transfer of Additional Copy or Adaptation.—
Any exact copies prepared in accordance with the provisions of this section may be leased, sold, or otherwise transferred, along with the copy from which such copies were prepared, only as part of the lease, sale, or other transfer of all rights in the program. Adaptations so prepared may be transferred only with the authorization of the copyright owner.
Regarding the Operation of Computers in Case Law
I would like to draw our attention to a significant series of caselaw known as the Mai Trio, which establishes how computer software may be used according to the 9th Circuit Court of Appeals:
Mai vs. Peak held that the the creation intermittent copies for the purposes of operating a computer by repairmen constituted fixed works was not protected under &Sect;117, because too many copies were made, and the repairmen did not own the computers. Congress amended the statute to include a new exception for maintenance, but the precedent still stands when subsection (c) is not considered. Wall Data vs. L.A. County Sheriff's Department held that creating 117 copies for convenience did not constitute an essential step, amongst other things. Triad Systems v. Southeaster Express holds a distinction between licensees and owners found in Mai v. Peak.
Now, the Landmark filesharing cases A&M Records, Inc. v. Napster, Inc., 239 F.3d 1004 (2001) and MGM Studios, Inc. v. Grokster, Ltd., 545 U.S. 913 (2005) regarded music, television and movies, rather than video games specifically, but both companies levied a space-shifting defense, arguing that users could download content they already owned over the internet as a fair use. The courts found this argument unpersuasive in both cases. M.G.M. v. Grokster in particular was a 0-9 supreme court shutout.
This in conjunction with the statutory requirement to transfer the §107 copy with the original physical medium from which it was derived, the findings of the Mai Trio lends me to believe that unlicensed but still legal transmision of video game R.O.M. files over the internet is not possible, as Nintendo claims.
Creating and Using Your own Copies.
It should be hypothetically possible to create your own copy directly from the original copy according to the statute. However, case law presents us with some difficulties.
Atari vs. J.S. & A. and Nintendo vs. Bung Enterprises establish that video game cartridge copiers are not protected by §117, based on a reading that matches the spirit of the law rather than the letter of it, with rationale that may be held as questionable today due to technological advancements. Modern solid state hard drives and thumb drives resemble the stable solid state of old video game cartridges more than the mechanical hard drives of the olden days.
However, you might be able to argue a U.S.C. Title 17 107 fair use backup claim based on a similar rationale based in R.I.A.A. vs Diamond Multimedia. This case regarded putting music on a digital audio player, but its significance is that it delimits a distinction between a copier and a media reader: A copier is a dedicated device new media embodying the work such as a C.D. or by way of analogy the floppy discs you would insert into Bung's Game Doctor onto new media, whereas a reader relies on the computer, which is a legal multipurpose device, to do that for it. The cross-applicability of the logic is however, hypothetical.
In principle emulation is legal if you can legally get a copy of the game to interface with the computer, as determined by Sony v. Connectix and Sony v. Bleem. A difference here however, is that these are optical disc based games that any standard C.D. R.O.M. player can read, so you do not need to own a device of dubious legality in order to make the backup copy.
The D.M.C.A's anticircumvention provisions might pose some problems with that, since irrespective of the general legality circumventing copy protection is illegal, but currently there are some video game related exceptions which may help, described in 54010 Federal Register/ Vol. 83, No. 208 / Friday, October 26, 2018 / Rules and Regulation (lengthy P.D.F.) and summarized on Frequently Asked Questions About the Section 1201 Rulemaking as follows:
Video games for which outside server support has been discontinued, to allow individual play by gamers and preservation of games by libraries, archives, and museums (as well as necessary jailbreaking of console computer code for preservation uses only), and preservation of discontinued video games that never required server support
D.M.C.A. anticircumvention measures also only apply to games that are copy protected as described in U.S.C. Title 17 §1201;