If anyone is interested, here's a quick way to cheat and unlock all the secret rooms:
Open regedit HKEY_CURRENT_USER\Software\Game Maker\Scores\834524 and change:
* Rank1 = FNDPGLOAOBOCODOEOFOGOHOIOJOKOLOMDKDNDNDFEK
* Rank2 = JNBHGCOAOBOCODOEOFOGOHOIOJOKOLOMEBDHDMDF
* Rank3 = BFKOEJOAOBOCODOEOFOGOHOIOJOKOLOMDIDHDLDMEE
* Rank4 = GFGLDKOAOBOCODOEOFOGOHOIOJOKOLOMEACPEFDFEE