Are you using an emulation algorithm to do the TIA sounds or did you just convert the AUDF etc values at the source level?
I just tacked on a routine onto VBLANK that reads the TIA zero page locations and translates them to POKEY values. TIA only has 5-bit counters, so the frequency lookup tables are pretty small. It wasn't until much later that I found out where the sound routines and tables were. Also, the TIA audio counters run at 30KHz, so they don't map nicely -- that's why I ran paired 16-bit channels instead.
It might be possible to emulate the missing mode with a high speed IRQ, but it'd be tough to interleave with the display kernel. Since this was originally a 2600 game, it uses a lot of mid-screen color and sprite changes to make up for the otherwise lack of detailed graphics. It might be a little easier to interleave a 15KHz IRQ, if the error is low enough not to be noticeable.
You plan on any tweaking or mods - - or just leaving a straight up port? Either way, great stuff!
Just a straight up port. I don't think it'd be easy to add to this game without ruining it, somehow. A VBXE enhanced version is left as an exercise for the reader.
I would like to make a donation for this. Is that possible? Do you have paypal or something?
Nah, I can't take money for just porting someone else's game.
p.s. There are two other fabulous Atari 2600 titles btw that need a port hehe: Private Eye (Activision) and Barnstorming (also Activision IIRC)... is there any chance you could look at those too one day? I'd be very thankful AGAIN
Are you crazy? Do you have any idea how much of a pain just this one was? I had nothing to go on but a vertically moving ball on screen for days!
If I had to pick another one to do, it'd probably be Vanguard. The 5200/800 version was a lot closer to the arcade, but for some reason it just felt more sterile to me than the 2600 version. Raiders of the Lost Ark and Riddle of the Sphinx also come to mind, but the spirit of the former is already carried in Sir Galahad and the Holy Grail, and the latter looks like an utter nightmare of sprite abuse (although I believe it has already been disassembled).