The gameplay for Um Jammer Lammy is very similar to that of the first
PaRappa the Rapper, as you have to have to press the buttons you see
on screen, and follow the teacher that way if you want to stay afloat,
but improvise your own groove if you want to truly shine and become
COOL.
However, due to the switch from rap/vocals-based gameplay to the guitar,
Um Jammer Lammy posseses faster paced and more challenging stages.
Despite the harder difficulty, there's also a quality of life change concerning the game's timing, and this is made much more consistent, with you usually having to press on time or slightly early depending on the input time rather than it being all over the place between each line.
In addition, Um Jammer Lammy also has quite a few extra gameplay modes to unlock.
Parappa's Story Mode
After clearing stage 7 of Lammy's story mode, you'll unlock Parappa's story mode.This mode seems to be mostly aimed towards fans of the original PaRappa the Rapper game, and its stages are renditions of the songs from Um Jammer Lammy, although remixed closer to PaRappa's style.
In addition, it seems that Parappa's voice lines in this game seem to be rather heavily compressed...
Vs. Mode
Versus Mode is one of the two multiplayer modes in Um Jammer Lammy.There are two versions of VS. Mode, Lammy vs Rammy and Lammy vs Parappa.
VS Mode is unlocked in a stage-by-stage basics, with Lammy's solo stages unlocking Lammy vs. Rammy and Parappa's solo stages unlocking Lammy vs. Parappa respectively.