I had this same issue before with Bluestacks as well! Did you initially try mapping your keys using the Virtual Keyboard via Bluestacks? It does work but it's horrible for those held notes because of the delay.

Here's what you do: 1.) Get your transfer code and save it somewhere just in case something goes wrong.

2.) Delete any mapping you have made with the Virtual Keyboard. Close Bluestacks.

3.) Download this .cfg file. This file is called com.Ent.Liber.cfg. Make sure you know where it is in your Downloads folder or wherever you saved it.

4.) You're going to want to look through your files. Follow this path in a File Explorer window. C:/ProgramData/Bluestacks/UserData/InputMapper/

5.) If there's an existing .cfg file called com.Ent.Liber.cfg, delete it and replace it with the one you downloaded. You may have to use the search feature.

6.) Restart Bluestacks, adjust your timing if needed, and enjoy Ai Chuu!

Note #1: If you have tried mapping your keys already with the Virtual Keyboard, you may have to look one folder deeper to place the .cfg file you have downloaded. Again, if there's an existing com.Ent.Liber.cfg file, delete it and replace. C:/ProgramData/BlueStacks/UserData/InputMapper/UserFiles/

Note #2: The default key mapping is shown here. You can open the .cfg file using Notepad and then adjust the Keys as desired. The Keys are assigned from left to right, so if you wanted to change the 1st circle on the left, you'd have to change the 'D' to another letter. Be sure to use capital letters!

Note #3: The .cfg file was originally made by @Toudoucchi! Send him a thank you tweet if this has helped you as well!

Sorry for the lengthy post, I wanted to make sure I could be as clear as possible. Good luck!