Rhythm
While making the beats, I found that naturally I was trying to make a 2/4 tempo piece. After realizing this, I tried to make a 3/4 tempo piece too. But I found it hard to make a piece with tempo different to those two in this web interface.
The beats were represented visually what I can directly click to add a pattern which stood for some kind of drum or other instrument to the loop. At the same time I could see two cute guys playing relevant instrument above refering to the piece I made.
I think I had one assumption it had not covered yet. The speed were still lack of flexibility. Only a few speeds could be created such as 1x, 0.5x, etc.