@OK Impala!
This is masterful! I will not say more because spoilers. I think anyone who was involved in the original game dev will be able to have a game to sit down with and enjoy fresh & new like we all did back in the day! You kept faithful to the original while at the same time using game mechanics in interesting new ways. Well done! Well done indeed!
Thank you so much!

Feel free to share these words in a review, it will help other players to estimate whether this is a game for them!

I was really enjoying this game. Feels like a proper sequel to the original and improves on the original in every way.
When I pick up a 9th magic container, the screen completely glitches up and the game hard locks.
Hi! Sad to hear you broke your game!

You shouldn't be able to get 9 containers at all.

Did you start the game with 3 heart containers and 2 magic containers? Try starting a brand new game and check if that's the case. Then try renaming the ROM so your emulator creates a new savefile. This could be caused by you using a name for your Amida's Curse that was used before, so your emulator uses an existing savefile from another Zelda II game, messing up your starting conditions.
If this doesn't work. You should patch a clean ROM again and double check you have the correct Zelda II ROM. You should start with 3 hearts and 2 magic containers and should therefore never be able to get more then 8 of each (There are surely no more containers in the game). Would love to hear from you what the issue was.
Might I suggest a hard mode patch that increases the difficulty somewhat as I can understand why some might have an issue with that.
Thanks for the suggestion! I put a lot of thought and work in balancing Amida's Curse. For the average player, Zelda II - Amida's Curse is challenging, but fair. I can understand the wish from Z2 Experts for a "nightmare" version of Amida's Curse. But to do that wish truly justice, would require a complete redesign of all screens of the game.
Might I suggest another challenge for Z2 Experts? Try beating Amida's Curse by not picking up any Rupees (P-bags), Heart Containers, Magic Containers or Lifes. That's a great way of upping the challenge and will surely be pretty hard to reach the ending. Might be a lot of fun trying to pull that off!