I was really excited that my computer could run the intro and the Nexus at ~30fps, but it tanked hard in 1-1. Planning to upgrade later so I may just defer my replaying the game until then.
Look at Dolphin. It got faster and faster all the while increasing in compatibility. To note, that doesn't mean no regressions but it will trend towards bettering both. Most emulators both increase in compatibility and speed.