It's more like the genre doesn't hold up very well anymore. Especially with old ones, the gameplay is really monotonous in retrospect. Mashmashmashmashmash, jump, kick, mashmashmashmash, pick up something, mashmash.
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http://www.youtube.com/watch?v=7MwZfXy9mA4
http://osu.ppy.sh/stat2/shinytentacool-0.png