Okay I get what you're going for. Money doesn't matter as much as as people getting sick, people getting sick but recovering doesn't matter as much as deaths. In addition, you want to somewhat realistically model the difficulties of people ignoring isolation or quarantine as well as limited hospital and governmental resources.
As a pure simulator of those things, this is great, and a good education tool, and I want to stress I commend you for that, especially since I'm going to go on a math rant in a second and get pretty critical on the game aspect of this. So just like, remember that I *really* appreciate that and the work that went into it before the rant starts XD
As a game the design is pretty bad. You're telling me to get below a score that will be RNG determined 90% of the time. It's infuriating and bad design for a game. My only options as a player are tests, isolation, lockdown, and hospitlization. Let's take Zone 4 as an example. It has 40% compliance and only 10% observance of things to keep infectivity down. You start the level with 5 out of 25 people infected (says 24 total on intro screen but that's apparently a mislabel). Even assuming I immediately started the level by testing everyone and telling everyone to isloate and locking down *everything* with no regard for money (so making it hard to avoid going over par already), statistically 2 people who are infected will continue running around with another 8 healthy people, with a decent chance of getting them sick. Par is set at 5004, so if a *single healthy person* gets sick, I have to restart. To not get fudged, I'd need either every sick person to listen or the surrounding people to listen, and while the math on the second is harder to get, the first is ever so slightly over a 1% chance. So even being super generous with the second situation and going up to 5%, that means that only 1/10 times am I even going to have a *chance* to beat par on zone 4. While this might be a realistic model that's very useful for teaching us, it's a *terrible* playing experience, and it's only the third real level of the game.
Basically what I'm saying is, if you want to keep the realistic simulation there (which I know I'd prefer as well), you need to relax par a bit or it's just nightmarish to play. And its easier to teach people through things like this if they don't rage quit after a few levels.