EDIT: Both of these issues have been fixed in BizHawk 2.7. Thanks again!
Original message:
In Choplifter on BizHawk 2.6.3, the title screen automatically ends too early. It should play music followed by just over 6 seconds of helicopter blade sounds,
as heard here on console. But if you open the game in A7800Hawk, you will notice the sound effect is skipped and the game starts right away, even though no button has been pressed. The ending of the game also jumps back to the title screen earlier than it should, after playing the same piece of music.
What's more pressing, though, is a determinism bug in Atari7800Hawk, or possibly BizHawk:
1. Play
this userfile until frame 4151.
2. Once there, save a state.
3. Optionally, continue playback for another second to see the glitched reset that's supposed to happen.
4. Load the state in Read+Write mode and hold Up+Right for at least five frames. The reset will still occur.
5. Load state again and don't press anything for the same amount of time. (The reset will not occur.)
6. Repeat step 4. Although the same input is pressed, you do not get the same outcome (reset). You can try again and again, it won't work.
I don't know whether this creates a "bad" savestate, or if the glitch performs some operation like an automatic soft reset that gets interrupted, but either way this should be looked into.