Well done indeed! The story goes beautifully with the game, and love the game opening / title with the news and messages. Lots of great little touches made this enjoyable -- the shortcuts for choosing which ambulance, the route lines and even showing when the fuel will run out by changing the color of line, the hearts getting larger over time, the effect of a dying heart -- really all come together in a cohesive way.
At one point, one of my drivers was stuck refueling for half the level -- I think that must've been a bug -- but no other major issues with playability. I did wish there was maybe a bit more forgivability on heartbeats when you have an ambulance realllly close to a heart about to go. xD
I think I got most into it and most overwhelmed once I had three ambulances at my disposal. :D