MANUEL got me thinking about a Wild Western port.
At first I thought it was too simple of a game to need the Supercharger, but I'm reconsidering.
Using strips of RAM to display sprites/particles would allow this kind of kernel:
sta ENABL ;+45
Assuming that Y ranges from 0 to 160, that would require about 800 bytes of RAM. Using 45 cycles leaves about 25 for other displayed objects.
Those other displayed objects are:
1. The train in the center, which AFAIK doesn't really move
2. The train tracks in the center, which do scroll vertically.
3. Obstacles (cactus, rocks, etc.) which also scroll vertically.
If I draw those with the PF, making them symmetrical with a reflected PF, then I can do this...
sta PF2 ;+21
Which takes up almost an entire scanline. But I'd probably update the particles every other line (or even every third/fourth), leaving plenty of time to reposition the sprites.
1. Drawing trains and obstacles with the playfield. Might get ugly.
2. Controls? The arcade uses a joystick, an 8-position rotary controller and two buttons.
A) Use two controllers: Joystick in port 1, DC in port 2. Might work if you could operate the DC and its button with one hand. This might make a good 2-player variation, though.
B) Shoot in direction you are moving or last moved. Not sure how to have him jump on the train, though.
Don't really like A or B. Anybody else have any brilliant ideas?