By default, it has 8 tracks and 16 step pattern length but it is expandable to unlimited tracks and pattern length.
You can set the velocity for each step individually.
Best usage is with an external midi controller like monome or korg padkontrol.
Or build your own with encoders for each step, so you can control the velocity for each step and create eg. snarerolls in seconds.
Just assign 16 buttons to the 16 step encoders.
You can set the note value for the track by changing the "scale" item in the chain for each track.
In the example, they are mapped to trigger an impulse, but you can use them for anything you want.
Another trick is: use the step sequencer for jamming and then record the midi in impulse track. You can create unlimited patterns like this, but they are no longer editable by the step sequencer if you record them
Download:
http://www.frischglanz.com/step-sequencer.zip
the download is up for a limited time, feel free to mirror it if you want.