Please don't attach or link to game ROMs and similar files unless the license explicitly allows this.

Please include the following:

• Which console (NES, GB, ...)
  NES

• The full name of the ROM you are running, e.g. "Super_Tilt_Bro_(E).nes"
  Guardian Legend, The (USA).nes,
  Guardian Legend, The (Europe).nes MD5 43cce874046a0850bf62eb6452e89e6b

• The git hash of this repo and the submodule. Run the following: git describe --all --long --dirty=-dirty; cd retro-go-stm32; git describe --all --long --dirty=-dirty
  Can't do this for now, hope it's not required. I have problems even with olderzeus's fork as well
  Edit:

heads/main-0-ga5a9b8b
heads/main-0-g5f1dd2b

Describe the bug
When a lot of enemies are on screen (which on this game happens most of the time), the performance tanks a lot, until they go away. This does not happen on real hardware (proof: https://www.youtube.com/watch?v=ImwZBSo8Rvo)

To Reproduce
Simply boot up the game and start a new game, in less than a minute, when the blue meteorites start appearing and then chasing you, the framerate drops tremendously, while the audio is virtually unchanged.

Expected behavior
It should not slow down, like the real NES

Screenshots
I'm not really sure how to export a performance graph, so I can't help here

Desktop environment:

• Host device OS: Artix Linux
• Debugger: ST-Link v2 clone

Additional context
Clearly a nofrendo problem, probably with the mappers (or with the rendering)?