The song on the last race is the anthem of a Italian party named Potere Operaio, active during the 60's and 70's. Here the lyrics:
Compagni, avanti per il Partito,
contro lo Stato lotta armata sarà;
con la conquista di tutto il potere
la dittatura operaia sarà.
Stato e padroni, fate attenzione,
nasce il Partito dell’insurrezione,
Potere Operaio e rivoluzione,
bandiere rosse e comunismo sarà.
The levelling system is simply ridiculous and there is too much luck involved: the game become terribly boring when you get stuck waiting for a combo that never arrives. You should be able to store bonuses once you obtain them, because very often you have to use them uselessly in order to free tiles positions on the board.