If you are going to Osaka, you must visit this place called Shinsekai. It looks like a pop up town from an anime with large neon lights and decorated figurines. It is also well-known for a special kind of fried food called Kushi-katsu that is really delicious.
You should alight at Doubutsuen-Mae Station (動物園前駅), but you can also take Ebisucho Station (恵美須町駅). However, if you come from Ebisucho, you will not see the pufferfish and other cool decorations as you walk towards the tower. Above that, most shops at that side are closed at night and it might get a bit complicated and unsafe to travel alone although there were many policemen patrolling.
The iconic food at Shinsekai is Kushi-katsu, which is actually anything fried on a stick. It can be vegetables, meat, cheese or even mochi. The batter is extremely crispy and you can dip the food into a bowl of specially made sauce to eat. Do note that you are not allowed to dip your stick more than once into the bowl of sauce as it is for public sharing. The most popular restaurant is located somewhere below the Tsutenkaku Tower called "Kushikatsu Daruma". There is an English menu as well as instructions on the table. They have foreign staff who can speak English to help you with your order. Kushikatsu costs around ¥105-210 per stick and you get free-flow cabbage slices to balance the fried food. You can be full after having 10 sticks or so, which is very economical for something so tasty.
If you are not into fried food, a good alternative will be a pufferfish set meal at the restaurant with the hanging pufferfish balloon called Zuboraya. We ordered the ¥3,500 set meal that included dishes prepared in various way using pufferfish: raw as sashimi, grilled, as a salad, in a soup and as sushi.
Besides good food, there are also pharmacies selling anything from medicine and healthcare products to skincare products. The largest is Sugi Pharmacy that also offers on the spot tax-free shopping to get back your 8% tax when you spend more than ¥5,000 (tax excluded).