I've had a go at this mod and while I do enjoy it, there are many errors that have made the mod a lot less fun.
For starters, it appears that in later levels, less care has been placed into the mod. By Level 5, it became clear that you had cared less about the overall presentation of the mod, and cared more about creating whatever missions you could. As an example, in L5M2, Apu is told to "Talk to Apu", with the icon as Homer. Another example is L3M2, where the player is told to "Reach all the checkpoints before your opponent does" to begin the mission at the Krustylu Studios. There are also countless grammatical errors across each level. I think it would be wise to go back and edit most of the missions and make sure that they make sense.
The missions themselves are okay, but lack consistency in their difficulty. For example, L1M7 was perfectly doable with no difficulty, but I really struggled with L2M1. L2M6 is a mission that is actually impossible to complete if the player collects the last few monkeys on top of the monorail station, with their vehicle parked next to the stairs. I had to park my car outside of the Googolplex Theatre in order to head back to the stadium within the time limit, and even then, I only had one second left remaining in the WW2 vehicle. As the mission is called "In the Nick of Time", it makes sense that the player would only have a couple or a few seconds left at the end of the mission, and I guess that if the player were to collect the monkeys near the fire engine jump last, then they would have time, but it makes distinctive sense to get the nearest items first, rather than making a detour to another side of the area first.
There is also too much of a reliance on "lunatic drivers". Many missions which include this mechanic are incredibly difficult, due to how fast and strong the opposing vehicles are, versus the car the player drives. L3M5 is a prime example, where the "lunatic driver" makes the mission overly difficult, which made the mission less fun to complete. Some missions, particularly those in Level 4, don't even need to have an opponent. The hearse in L4M1 and L4M2 spawns outside of the boundaries, thus making them completely pointless. Many other types of missions were also repeated too often, such as following a vehicle and collecting 7 items.
I was expecting this mod to be in no way connected to the actual plot of the proper Hit & Run game because of the title, and I feel like that was your intent, but I felt like by Level 3, you sort of gave up on good mission ideas, and decided to use the main missions of the game, and effectively replicate them with a minor tweak.
I'm not suggesting that you completely redesign this mod, but what I am saying is that you should take extra care when making a mod, and go back and make some adjustments. You can very easily remove the "lunatic drivers" from half of the missions that contain them, and the mod would immediately be a better experience. When starting a mission with a blue circle, the task box could say "Start the mission in the blue circle" or something along those lines, rather than "Drive to [location]" as most of them say. I'd also increase the timer by 5-10 seconds for certain tasks in several missions. I understand that the mod is called "Super Challenge Mod", and I was definitely expecting a challenge, but I wasn't expecting something complicatedly difficult and near-impossible.
Thanks for reading, and I hope you take into consideration what I've said here. This is some simple constructive criticism, and shouldn't be taken personally.