Um Jammer Lammy was free on psn plus and I decided to play it 'cause nostalgia and I can't even pass the first level 
I don't know what I'm doing wrong. I played these games all years ago and am usually not that bad at rhythm games.
Parappa and Lammy don't play like other rhythm games.
In Parappa, you listen to the lyrics.
Like say:
In the rain or in the snow
Got the got the funky flow
Maybe the game will look like this:
Where /_\ denotes the triangle button.
/_\ (in) /_\ (the) /_\ (rain)/_\ (or) /_\ (in) /_\ (the)/_\(snow)
/_\(got)/_\(the) /_\(got)/_\(the)/_\(fun)/_\ky)/_\(flow)
That's a button press for every single syllable.
You press the buttons to the lyrics, not to the icons that appear on the screen like every other music game.
Lammy works in a very similar way.