You unlock versus mode in level 14, however, if you're in PC you can modify the save file to unlock everything.
Look for the folder %appdata%/PVZ_ND and open the file save data.ini
Then set the variables "niveles" to 74, "dinero" to a higher number to buy the shop, and all "hard level" to 6 to unlock all hard mode plants.
If you're in android, I guess you could join the discord server and ask if someone can borrow you a gamejolt account with everything unlocked.
And almost all of the music is a remix :b