Great Game 5/5 A lot of upgrades and in game achievements / challenges
Music
Suggestions
Better Start over Menu(Cant see start over button or what ever)
Starting out Cash
Boss Health doesn't always show (Go to Shop and return)
Achievements
Survival mode (Upgrades removes Upgrades)
Health Packs
Power Ups
Different background (gets boring after awhile)
Multiply Songs
Score multipliers (X2 x4 ect)