Asian

Shabu Shabu: Just like Miu in Amsterdam, this is an all you can eat style Japanese/sushi restaurant. My absolute favorite when I am in Rotterdam.
Takumi Dusseldorf Netherlands: Feeling in the mood for ramen? This place has you covered! The portions here are big so you will leave with a full belly of noodles. I recommend the tonkotsu ramen, can't go wrong with it :)
China Town Dim Sum Rotterdam: Fun little place you can go for dim sum. Most of the items are fairly reasonably priced, good for sharing with a group of people.
Grand Garden Restaurant: Great place for that authentic Asian cuisine. Located inside the NH Hotel Rotterdam.
Seoul Sista: All you can eat Korean BBQ with a great variety and selection of foods.

American

Gracy's: American style 50's diner in the heart of Rotterdam. If you are in the mood for burgers this place is a must try!
Encore Bar and Grill: Here you can customize your dinner from your choice of meat/fish or burgers with sides and a salad. Great service and drink selections.
Rotown: A lovely bar/restaurant. They serve wonderful food as a restaurant and as a bar frequently have live music of all sorts. So whether you go for the food or the music, this is a great place to visit.

Dutch/Traditional

Old Dutch: On the more expensive side, Old Dutch features classics with a fancy flare. They also feature a fun selection of drinks as well as prix fix courses that change daily.
Prachtig: Set right beside the well known Erasmusbrug on the water, this restaurant not only gives a picturesque view, but also gives a great selection of traditional fare to choose from.

Sweets/Desserts

Poffertjessalon Seth: When in Holland, poffertjes are a must have! These tiny pancakes are served with icing sugar and your choice of fruit.
Bakers Dough: Craving cookie dough and ice cream? This place serves raw (but safe to eat) cookie dough with your choice of fruits and/or ice cream.
Roll'd Up Ice Cream: Watch in awe as your favorite ice cream is made in front of you. Pick your base, mix-ins, and toppings to create your own masterpiece! There is no website yet, but they are located close to the Market Hall.

Seafood

The Fish Market: A reasonably affordable place to get some of the best fish around! Definitely give this place a try.
Zeezout: More on the expensive side for seafood, Zeezout is praised as being one of the best fish restaurants in South Holland. If your budget allows, this is a place that can't be beat.