Hi Tumulte and thanks for your question,
The sequencer is not yet available with chromatic notes. For now it only works with 7-tones scales that you can choose from the scale menu : short press on the Bass clef. To go up or down in octaves you just have to click on the "+" and "-" signs. Concerning the velocity, it is recorded every time you tap on the sequencer, we just don't have a visual feedback yet, we planned to implement a color gradient depending on velocity in future update.
Thanks for your concern !