To be fair, Unreal *does* have some 2D capabilities, otherwise this game wouldn't exist on it. But like, it's hardly a lightweight engine by any fucking means. Hell, the editor itself is like, what, almost 30gb in size? That's not even counting any optional packages you can choose to install alongside it, it's fuckin outlandishly bloated and you gotta just wrangle with the stupid thing for days on end to get it to run on lower end machines or remove all the built-in shit like VR addons or whatever to reduce the file size. It's why the dev seems to be stuck in a back and forth cycle of trying to fix new bugs or graphical issues (like when sometimes the sprites have filtering enabled and they're all blurry lmao) rather than adding new content. Unreal absolutely is not friendly to new game devs.
Gamemaker is pretty much a 2D-exclusive(??) engine and can do the job pretty fine, but IMO Godot is the best for 2D and I can definitely attest there's more than enough features to whip up anything half-decent *and* you don't need a fucking degree in quantum mechanics to get the engine to do anything you want it to, unlike Unreal lol. I got bored a few weeks back and whipped up a similar kind of project and it really didn't take too much effort to get a similarly-looking and feeling player up and running. I speak as someone who definitely would stab a power outlet with a fork if I had the chance, so it's pretty easy to get into the swing of things even if you're a non-programmer. Getting started is the slow part ofc, that's like, the biggest hurdle for any game project lol.
the content we do have is really good, but I've been kinda waiting for a bunch more updates at this rate since there always seem to be more bugs than progress, and I think even the dev has been talking about this on their discord a few times.