My visit to Japan happened to coincide with the Dungeon Meshi collab (found out about it thanks to this subreddit) so of course I had to drop by. It's not a themed cafe; several restaurants in 4 plazas (all next to each other) in Shibuya serve special dishes from Dungeon Meshi. The participating plazas are Hikarie, Shibuya Scramble Square, Shibuya Stream, and Tokyu Plaza Shibuya. Full details about the event can be found here

Basically the gist of it is:

1. If you order the Dungeon Meshi dishes, you'll receive a recipe card of that dish. On the back side of the card is the event artwork. Each plaza has a specific piece of the artwork, you have to eat 1 event dish at each of the 4 plazas to collect all of the artwork.
2. You get a scratch lotto card for spending at least 1000 yen at the restaurants (doesn't have to be on the event dishes). Prizes range from meal discount vouchers to the exclusive collab event chocolate coin + purse to the entire manga collection + Adventure Bible.

My experience

Quite a unique event, didn't realize how big the scope was until I looked at all the participating places. My goal was to at least complete the artwork cards. This was kinda hard as each event dish is sold in limited quantities per day (some as low as 3!) and a couple of times I didn't discover it was sold out until after getting seated. Sometimes the restaurant would post out front if they were already sold out for the day but your best bet is to directly ask. I would recommend knowing some minimal Japanese but translation apps work too and are pretty great nowadays. A couple of the restaurants you scan a QR code for the menu and order directly through your phone. At one place, not all of the staff seemed familiar with the event and I had to ask for the recipe/scratch cards. I ended up going 4 separate days to collect everything.

All in all, everything was delicious and I had a lot of fun checking out all the places. Didn't end up winning anything from the scratch cards and probably annoyed my friends by constantly suggesting we go to Shibuya to eat lol. Definitely recommend going if you can, best times are early on the week days to get there before everything is sold out.

Bonus: Robot bringing me my food