3D MIDI visualizer (also support 2D view).
You can move around in 3D space.
Different perspective modes.
You can customize alot of things (note color, length, size, background image, etc...).
Require high performance PC if your midi file contains huge amount of notes (like black MIDI files which usually contains tens of thousands of notes), but for most other MIDI files it should run smoothly.
Can't resize window.