It works surprisingly well! It doesn't fit into the console weird like I thought it would, and grips the internal connection just the right amount not to feel worrying.
All the games work, and the games that support battery-backed saves are saved individually. I was expecting much worse from a product that looks like this from AliExpress.
There really isn't much dialog to Innsmouth, but all the JPN exclusives that can benefit from translations have been translated. (Though all the JPN roms on this multicart are unpatched original roms).
OEM retail carts do not look like this multicart!