@Paracite Any particular reason you opted for "Shinkai fish burger" instead of "Abyssal fish burger"?
Also, while I can understand why you altered "having" into "eating" to parallel the commercial tag line, I think the wordplay works better using "having" instead, and you would be forgiven for tweaking the tag line for the sake of a better punch line. My two bits, anyway.
The delivery box in the next panel has 'Shinkai Burger' written on it, so it's the company name, rather than a burger made from abyssopelagic fish.
I.e. A fish burger from 'Shinkai Burger' and not a 'shinkai burger'.
I didn't change it to eating, I had 'having' originally for the very reason of the joke working better - it was changed by someone else to match the ad (which I have no idea if there's a similar one in Japan). As the joke is based on having the same line twice, it has to be identical regardless of how it's worded .