Mild warning: Collecting coins out of order may cause a glitch.

[The-Man-In-Black]

So every level beyond level 5 has a "Bacon Coin" in it that you have to collect in order to unlock the "Extra Levels".  

 

Collect these coins in order.  If you complete a level without collecting the coin, go back and replay the level before progressing to the next one.  

 

If you collect the coins out of order, there is the possibility that the count may glitch, leading you to a situation where you have 23/22 coins.  If this happens, the old lady will not unlock the 2nd bonus room for you, and the only option you have is to delete the save data and start from scratch.   I had this happen to me because I forgot to grab the coin in level 6 for some reason.  

 

On a different note, you do not have to complete the level in order for the coin to register as collected.  If you do have to go back and replay a level to get the coin, you can exit the level as soon as you collect it.  

[visighost]

I collected them in order but still ended up with 23/22, forcing a restart. I think I died as I was collecting one, which may have screwed up the count?

 

@RatalaikaGames, are you aware of the bug?

[ProfaneCreation]

This is the worst game ever, completely broken. I've completed it twice in a row perfectly & the door won't open.

 

Ok, got it the third time. I'd recommend not quitting to the main menu at all, that's the only thing I did differently.

Edited April 20, 2023 by ProfaneCreation