Weak watch, won't watch again, and can't recommend except for HUGE Rugrats fans.
As the origin story for Dill Pickles, it very clearly is going to deal with "Where do babies come from?", but I think this is the closest the Rugrats franchise has come to addressing death with its audience.
I don't think the nostalgia I had for Rugrats was strong enough. I'm seeing all these characters I loved, and just feeling nothing. I'm hearing these (fantastic, voice-acting) ladies doing baby voice, and I've seen other movies where ladies do baby voice and they're just not nearly as long as this one.
I might have been able to get into the movie as it actually has a decent story (thought it focuses on the parents more than I'm used to), but they decided to play with rules that involve how babies talk. They clearly present new-born babies that not only talk, but talk eloquently about "Missing their old womb" (sounds like a baby saying "room"). Dill, barely talks. in fact, he talks to the babies like the babies would talk to the adults, and they refer to him as a baby.
While they should be toddlers and speaking a lot more than they should, part of the premise is that they're babies that talk to each other, but not adults. It almost paints the picture that Dill was born retarded, but refuses to address it, even if it applies it directly.
It really broke the movie for me, as it's the chief mechanic behind the babies' A story line that is the basis for the parents' B story line.