A clear SLAPP suit, hope T2 gets embarrassed, they must have very dumb lawyers. People saying there is copyrighted/stolen code are wrong. Try to understand the history of unlicensed games, tengen/atari vs nintendo, sony vs bleem, galoob vs nintendo etc.. there is a clear precedent that you can subvert companies licensing requirements as long as you dont distribute modified works and turn a profit. This type of engine wrapper is exactly like a game genie, useless on its own, not a derivative work but combine it with the official (hopefully purchaced) game and you have something better than the original, for personal use.
"unlicensed games"
Some company tries to say our device, our rules, we determine what runs on it.
Courts say nope consumer protections say their device, their rules.
Company tries to include trademark asset in required key for unlocking console.
Court says nope, not a valid use of trademark.
Company tricks trusted party of those making device into sending code that is used to bypass protections (This would be Atari vs Nintendo, nice example of "unclean hands"/privileged information thing I was on about earlier actually).
Company doing the tricking gets slapped for that, though theoretically is allowed to continue were it not for that case.
Company by its own ingeniousness manages to bypass protections (this would be Sega vs Accolade).
Company is told nice one by the courts, carry on if you want. Affirmation of the earlier thing that would have worked if Atari were better engineers.
Galoob vs Nintendo (the game genie case)
Users are indeed allowed to mod code running on their systems without it troubling IP law, and devices to do so can be sold.
Sony and Bleem had two major aspects really.
Generally though this would be where emulation was generally clarified, and arrangements of chips deemed hard to copyright, emulation itself also having substantial non infringing uses even without that (code making, forensics, disabilities, mere use of code you legitimately own aka interoperability that also feeds into hippie whale hugging where you don't want waste if you wanted to go there as well...). Sadly came too late for Bleem that had since run out of money but it is a worthy legacy.
To add on to the list you probably want the various World of Warcraft cases. Mostly that memory and code copying to it/executing in it is part of the normal operation so go do one Blizzard when they tried that on.
All great cases to explore if you want, and right decisions in each of them as far as I am concerned (a rarity in a lot of IP cases and law -- the US has some howlers as far as I am concerned with patents on DNA, patents on software, prior art being basically a non thing in patents, obviousness even more of a non thing in patents, most of the DMCA, copyright extensions... the list goes on).
None of this however says word one about you taking some code that you have no rights to, disassembling it, tweaking it a bit so you can assemble it (or compile it), maybe adding a few comments and releasing that as a whole functional piece of code to the world as being a legit act and not in stark contravention of derived works preclusions. As far as I am aware (and it is certainly the assumption TakeTwo/Rockstar are operating under) this is not a wrapper that acts as an interpreter/bridge/hypervisor/emulator/abstraction layer between the code, a different host machine and its original assets, or a legit recreation of the code that happens to support the original assets in their original format. It is an oh so tempting and effective method of quickly and with minimal resources (both in the project and destination machine) achieving interoperability and much more besides (see list of improvements seen for Mario 64 for but a small list of possibilities there) but I can see no way of this being allowed and still having any kind of usable copyright apply to code in any way whatsoever.
Now if some legal/politico types (or possibility military/national security -- see history of encryption, and probable future of unregulated cryptocurrencies if "think of the children" does not get there first) decided to get a bit uppity and try to block decompilation technology (see also "hacking tools", though the EU courts and lawmakers tend to be more fond of that one and get slapped down hard as well) then I would be most upset and consider that a breach of good sense, though as it would also effectively vanquish coding, the security industry and such overnight then I am not predicting it from more than mouths of a clueless politician that does not know his arse from an atx power supply.
"as long as you dont distribute modified works and turn a profit"
That is certainly an aggravating factor, and one that will see lawyers perk up (money in from business being something you can take to have in turn funded the case, as opposed to a bunch of broke bedroom coders that you will struggle to collect from), but not the ruling or consideration of any of that. Indeed the Galoob thing was seeing them get the right to distribute something to modify a work and gain profits while at it.