What is the main difference in playing the organ versus the piano?

The biggest difference that you will notice at first is a very different fingering style—you play sort of legato, since there is no sustain pedal. To put this another way—when I am playing piano and I am holding down the sustain pedal, a note or chord will continue to sound even if I release the keys, either until I release the pedal or the note/chord decays away. But when I’m playing organ, I’m using my foot not to sustain but to control the volume, so when I release a note or chord, the note/chord stops right then (on the other hand, it will continue to sound for as long as I keep the keys pressed down). The keys also have a different feel from the keys on a piano, plus it doesn’t matter how hard or soft you press them, the volume will be the same. Controlling the volume with your foot will take some getting used to as well—on piano I pump and release the sustain pedal more or less constantly, but when at the organ I use more of a steady pressure on the volume pedals, with changes that tend to be more gradual. This will feel very strange if you are used to sustaining.

There are many other differences (for instance, learning the registration, self-accompaniment, and learning the pedalboard) but these are the ones that will really challenge you at first.

The piano has 88 keys. The organ has multiple keyboards, plus you need to use the pedals and also learn to make different sounds. Much more difficult than the piano, but oh how beautiful. Good luck.

The organ will be just as hard, if not harder.

An organ can have multiple keyboards, including one for your feet. Generally, piano is the place to start.

the organ is annoying

piano isnt