Thanks for the difficulty feedback!! I have played so many times these races, that it is very hard for me to assess how hard they are! I'll definitively adjust! Will make Alleycat easier 
(I am assuming you mean the version of Alleycat for stock cars, right?, since you find that circuit one more time later on)
I've also considered giving passwords every time you complete a category. But the game is not that long, so, not sure... but still an idea I might add (if I can find the bytes to fit it in, of course, hehehe)
And good to know about the joystick! In principle it should work (I reused the code from XSpelunker), but I have to admit I didn't test it. So, will check it out one more time!!
Your README's are great as well
Something you forgot to update: "Some notes and useful links I used when coding XSpelunker"
Skid Vicious, in addition to Sid Vicious, is a reference to 4D Sports driving
Oh, I could have bet that that was a reference to PC Game Stunts!!!! 
http://www.stunts.hu/stuntsrus/flowersforskid_files/2.JPG
https://i.ytimg.com/vi/SThh5FjAlL4/hqdefault.jpg
Skid Vicious, in addition to Sid Vicious, is a reference to 4D Sports driving
Oh, I could have bet that that was a reference to PC Game Stunts!!!!
There was two versions released of Stunts... Stunts "1.0" and "1.1"... In between they released the game in Europe with name "4D Sports driving", but they are all the same game, just a bit bug fixing has been done between the different releases.
Yes!!! I knew it as 4D Sports Driving, but in the internet it's usually known as Stunts! 
and indeed, I wanted that Skid Vicious to be the agent!!
@Uninteresting: yes, exactly those objects with IDs in the TMX files are the waypoints for the AI. Each of them uses 4 bytes before being compressed with Pletter. So, I would say 2-3 bytes per waypoint in the ROM. You can see them in the assembler side, for example, if you open the "src/maps/track1-meta.asm" file, at the bottom of the file. I set a limit of 24 per track, to save RAM when the track is decompressed to RAM, and that defines how separated they are in the tracks. As for how other games did it: waypoints is the most common approach, but some other games had different solutions. For example, some early games by the Oliver Twins just had a "prerecorded replay" of a human playing that was played back during gameplay, simulating an AI. Waypoints are still one of the most common ways nowadays for racing AI
I've gotten quite a few bug reports so far (thanks to everyone for reporting!!!), so I will try to fix as many as I can before the deadline and upload an updated version asap!
