Doing some drudgery-type tasks on this lately, nothing flashy like new GFX - but I think I'm a good amount of the way through the doldrums now, and it's almost time to do some more fun stuff like making maps for a campaign-mode and getting some sounds implemented. Hooray!
A notable change is that the track files now store four separate replays of varying skill levels to compete against (based on the Trackmania setup: bronze, silver, gold, and the track's author), and you race against all of them at once:
Seeing all these other cars is a pretty nice quality-boost to me, though it's also cemented the idea that I need to lock the game to 30fps. It's a little disappointing since I've been testing at 40-50fps for most of development, but to be honest the difference is only really noticeable to me in the desktop simulator...so if it still looks good on the device, and it means I don't have to compromise on the stuff that I've already added to the game, then I think it's a worthwhile tradeoff. Maybe a really smart programmer could get it back up to 40 or even 50, but I'm getting continuously more certain that this hypothetical programmer isn't me!
I've also started to dip my toes into the desktop companion-app, which I've decided should be a web page - it's using the relatively recent SerialPort API in javascript, which only works in chrome, edge, and opera...but that seems okay. Even if you're a mac user who also hates chrome, you still have another option with opera, at least. If you really, really don't want to use any of those browsers, I could also let you download the track file and upload it to your device manually (by putting it into data-disk mode). There's no track i/o yet, but I've got the site connecting to the device and receiving messages, so I'm feeling good about the idea being generally-possible.
The real advantage of this setup is that it'll let you share a track you've made as a URL, which takes someone else to a web page which contains the track/replay data and also the instructions/mechanism for getting the track onto your device, all in one place. Aside from sharing a custom track with 4 replays/medals, it also seems like it'd be nice if you could share your best replay for the daily challenge (a procgen track seeded by the date), so you could basically "chess by mail" the daily challenge with a friend (or your social media followers, if I'm lucky).