This hotfix makes it so the Steam Achievements for The Time Trials are now properly hooked up! There was a massive oversight on my part, and I failed to fill in key information into a specific file for it to work. The 4 new achievements should now be achievable! I'm really sorry to those of you who put in the work to beat all the races, only to find that you didn't get the achievement.
Also, I posted a Guide with a breakdown of how to get 100% on your save-file.