People think MMX2 was the best? I mean I love the game but I always though MMX was the most popular.
But how about Sonic? Sonic 2 > Sonic 1
Mega Man 2 > Mega Man 1
Assassins Creed 2 > Assassins Creed 1
Mario Kart 64 > Super Mario Kart
Smash Bros Melee > Smash Bros 64
Super Mario Bros 3 > Super Mario Bros 1 & 2
Silent Hill 2 > Silent Hill 1
There are countless examples of sequels besting the originals. I have a theory of why originals tend to beat sequels in movies, but the reverse is often true in video games:
There is no gameplay in watching movies. The whole thing is based on story. Oftentimes the original movie of a series is what defines the series and everyone bases every subsequent title in the same series in comparison to the original, and people often find that the original is best because that's the first one they watched or that movie is what defines the series to them. Likewise, music artists with a killer first album are often plagued with fans complaining that none of their other albums measure up to the first album just because they set the bar so high and every single album afterwards is judged solely on that first great album.
As for video game sequels, they more or less tend to take what the games before them did and improve on it. Since there is so much more to base a video game on than you can a movie, since it is interactive, good developers tend to see what gamers liked and didn't like in the first game and improve on weak areas of the first and keep good areas in the sequel. For example, Smash Bros Melee did everything Smash Bros 64 did, but better. There's almost no contest there. It's a bigger, better, more refined gameplay experience. Or take Donkey Kong Country 2 vs the original. DKC2 had better level designs, more varied levels, better gameplay, more memorable music, and while DKC1 was fantastic, they kept the best elements of the original while refining some of the weaker parts of the game and adding a few new things in like the piggyback move. As we know, this isn't always the case. Usually sequels tend to have better gameplay than the games before them but games based on story, atmosphere, or overall creativity might work best for the originals. Take for example Metroid Prime, a game that is very near and dear to my heart. An absolute masterpiece. Metroid Prime 2, while good, doesn't match up to the original despite having almost identical gameplay and atmosphere. Why is this? To me, the game design doesn;t feel fresh because it's not the original, whereas MP1 defined that series, much like a movie would, and I also enjoyed the story more in MP1.