What videogame sequels you think ended up screwing what was done in the orginal?

[JNK]

not really sequels, but further installments in the series.

Gothic 4 (1,2 were awesome, 3 was great, 4 was ...)
Harry Potter PC Games (first 3 awesome, 4-8 awfull)
Guild Wars 2 (liked 1 much, much more. 2 wasnt "bad" though)