It shows symptoms of having limited resources, but it doesn't look particularly stressed, and it's doing remarkably well, considering.
It shows signs that it would like more phosphorus (thin stems and small leaves).
It might have nitrogen-deficiency (or else disease symptoms), considering the yellowing lower leaves.
I would guess that it needs more fertilizer (I see signs that it might appreciate more nitrogen and phosphorus), more light, and a larger container.
It might appreciate more light, considering internode length and the mild leaf miner damage.
All things considered, though, it's doing well, and the fruit looks good (the fruit itself doesn't look stressed--yes, fruit can look stressed). It's possible the fruit would be larger in different conditions, but there are tomatoes that size and smaller; so, you never know until you experiment. However, I'm guessing by the growth habit and how well it's doing in that container that it's a cherry tomato.
The plant doesn't show visible signs of being stunted, which is a great sign.
The container could stand to be larger (ideally). Giving it a larger container would probably increase the stem thickness and leaf size, too (so, maybe it doesn't need more phosphorus after all, particularly).
Since the plant is so large, you have a unique opportunity here, which could make up somewhat for a smaller container: foliar sprays. The more leaves there are to get fertilizer, the more benefit you should notice from the foliar spray.
There's a product called Silica Blast that might thicken the stems.