Also worth mentioning are the available SA-1 optimization patches.

Axelay
Contra III
F-Zero
Gradius III
Race Drivin'
Super Castlevania IV
Super Mario World
Super R-Type
Super Mario World Widescreen

Super Metroid should soon follow with an expected 2023 release.

One minute video showing the game rom upgrade difference:
https://twitter.com/HackerVilela/status/1363250560133193733

Source:
https://github.com/vitorvilela7