While I'm pretty aware of who Doraemon is and the enormous franchise power it represents, I don't think I've ever watched a Doraemon film or TV episode in full. But the little blue cat robot is so ubiquitous in Japanese media that it already felt quite familiar. The fact that it's aimed at kids and isn't very complex also made things a little easier.
That said, the film is a bit of mess. Doraemon travels back from the future to help Nobita get the girl he loves, but the plot was surprisingly fragmented. It's a constant repetition of Nobita getting an idea, Doraemon providing some sci-fi gadget to help, only to result in inevitable failure.
The art style is nice enough, especially since it's the first time they used CG. It's a pretty simple style, but cute and pleasing to the eye. There are a few decent gags and the jolly tone makes for an easy watch, but overall it felt too much like a collection of 10-minute episodes strung together to make a feature-length film.