I got a(n) A- on medium! My score was 1843338 with a max combo of 134. I scored 194 perfects, 128 greats, and 25 goods. I got only 3 bads and 5 misses! I was playing on 5 speed and had 0 crazy options on. Great game, I like it! Play it here: http://www.thorgaming.com/games/3926/feel-the-beat.html
there are some very disturbing bugs, for example soldiers just dieappear without beeing attack, and on the building screen all stats are undifined. not nice....so i lost my lvl 100 soldiers, with which the game isnt hard anymore ;)
i like this game, when u have full upgraded gold income and u already have the hammer, u should increase ur castles def and hp, then in one wave, kill all monsters but one firecreep or whtever this is. and then judt wait. it should just do 1 dmg to ur castle, so u have to repair it after some minutes, but u just get 500 coins per second, u can do this as long as u want, just wait and dont let ur castle go down. ...so its very easy to get gold.