Amazed at their good taste!
The opposite. The first film is one of the best screenplays of its era and tells a touchingly human story that is merely facilitated by time travel. In the sequel, time travel
is the story, and it's a fairly slapdash plot with a lot of weird holes, awkward changes to the characters to set up the third film (Marty's obsession with being called chicken, Doc's fondness for trains and the Old West, etc.), and works hard to undo a lot of the outcomes of the original film. The entire Old Biff thing makes no sense, not just in that he somehow knows how to operate the time machine but that Doc Brown, who repeatedly states the dangers of time travel and the hazards of potential misuse, apparently leaves the fucking door unlocked and the keys in the ignition when he parks the most dangerous thing ever invented on the street in a neighborhood repeatedly acknowledged as crime-ridden.
The first film is a masterpiece. The sequels are okay but nothing special in terms of storytelling, although at least the third remembers to be character driven instead of being a mindless plot march. The future sequences of 2 are a lot of fun and the most memorable part of the movie, but the rest of it is a bit of a slog. It's not in any imaginable way better than the first, and if you're just talking about movies that have time travel as their focus instead of as a device to get to the real story (as BttF1 uses it), there are at least half a dozen better and more thoughtful uses of the concept than BttF2, including the first Bill & Ted movie.