As far as difficulty, Expert mode is still pretty freaking hard.

After completing a marathon with the Hard difficulty setting, Expert mode is made available.

The audience bar functions similarly to that of Expert mode, but falling to zero doesn't result in an immediate game over.

This only applies to Easy, Medium and Hard modes; in Expert mode, only up and down movements are allowed.

Also a feature removed is that there are no extra stages added on to the Beginner, Advanced, and Expert modes.

By completing the game on Normal, Expert mode can be unlocked, and upon completing it, an extended ending can be viewed.

The Expert mode has more pronounced draw and fade effects, making the timing of the third click more crucial.

After the player defeats the Metroid Prime creature on the Impact Crater table, the game unlocks a higher difficulty level, Expert mode.

In the Options menu, the player can choose to play the Super Battle mode on "Normal" or "Expert" modes.

A third "Expert" mode can be unlocked during gameplay, adding the difficulty of the original game's expert setting.