Rice cakes are rice with the air pressed out. 150g of tteok, roughly 12 to 15 pieces, is 215 calories, the same as a full bowl of cooked rice but in a much smaller pile. That is why a paper cup from a cart feels heavier than it looks, and why you feel full after one serving even though it is only 335 calories.
The sauce is gochujang, gochugaru, sugar and syrup, and a 60g ladle of it is about 50 calories with 10g of sugar. It is not the calorie problem. The fried add-ons are. A single tempura-battered item (튀김) is 100 to 150 calories, an egg is 75, and a slice of cheese melted on top is 65. Cheese tteokbokki with two twigim runs past 600.
Bunsik shop plates are usually bigger than the cart cup. A 3,500 won plate can be 300g to 350g, and the popular takeaway brands like Sinjeon list 137 kcal per 100g, so a 400g takeaway container is 550 calories before the sundae and twigim you ordered on the side.