Just wanted to mention that, to me, your gameplay logic description is a bit off (bolding was my emphasis): Thus, we have misses and hits counters. If I push the key at the wrong time, at the wrong place, I will have misses. Now if I push the key at the right time, in the wrong place , I will have ...

This time I'm trying to do a game like Guitar Hero. But instead of a guitar I'm using drums (that is, a key-based drumming game). We would have two targets (squares) named HitterTouched1 and HitterTouched2 through which the keys drawn on the screen must pass (collision part). That collision part was...