I've not been working on this with as much gusto as I'd like, but I've made the changes to enable the title screen to work.
Overlaying Screen 2 showing the FlappyBird logo on top of the dual-playfield screens.
Haven't repositioned Flappy to the side of the logo nor made the logo do a sinewave up/down.
The original game does a quick fade-to-black when the user begins a game. AMOS' built-in Fade command won't work on more than one screen at once, which meant doing a bit of maths to figure out how to do my own fade routine. I have never before done one.
Dim PAL0(31),PAL2(4)
Screen 0
For N=0 To 31
PAL0(N)=Colour(N)
Next N
Screen 2
For N=0 To 4
PAL2(N)=Colour(N)
Next N
For I=16 to 1 Step -1
Screen 0
For N=0 To 21
T=PAL0(N)
Colour N,(((T and $F00)/4096.0*I) and $F)*256+(((T and $F0)/256.0*I) and $F)*16+((T and $F)/16.0*I)
Next N
Screen 2
For N=0 To 4
T=PAL2(N)
Colour N,(((T and $F00)/4096.0*I) and $F)*256+(((T and $F0)/256.0*I) and $F)*16+((T and $F)/16.0*I)
Next N
Wait Vbl
Next I
I tweaked the way Flappy 'flaps', too. It was difficult to get him from a low gap to a high gap. I'm going to look more closely at video of his movement, but for now I've made it so that 2 or more quick taps gives him a bit more vertical delta.
If IN$<>"" or Mouse Click Then DELTAY#=Max(-4,Min(-3.25,DELTAY#-3.25))
Seems to work well.