After Burner II is an updated re-release of After Burner.
Besides extra levels, a few new enemies, a few touches at the soundtrack and more disposable missiles, the biggest addition is the ability to slow down or speed up manually.
The rest of the gameplay remains identical.
Despite being called After Burner, most ports to home computers and consoles are based on this version.
The NES, Amiga and Commodore 64 received two different ports with significant technical differences.