A good effort
Its a good effort, and theres a lot of time put into the songs, however, the interface is poor. There seems to be almost no actual creativity put into the UI, and the stick figure almost makes the game feel like its telling the player "I wasn't willing to put more time into this, just deal with this stick figure"
Also, with rythme games the "level" design is critical. The reason Guitar Hero is so good is because the levels have a lot of time and thought put into them. The path the player takes with the buttons have to be well thought out. Sometimes it requires recreating the song accurately, and sometimes its just about making somehting that feels right to hit.
In this case, I see niether of these situation. Some times it seems to follow the songs, other times it just seems hastily thrown together.
My last complaint is is the choice of buttons. 123 and 4 are poor chosen. The keyboard has little representation for finding these keys. Using ASDF would have proven more successful as the keyboard it self has a small indent to let your fingers know.
Anyway, either way, its a good start. I think you need a bigger team working on the game end. Its just as important as the audio itself.
Keep it up.