Overall an interesting and short experience, but I didn't really understand the difficulty scaling.
At first I couldn't dial and call a full number, but after I refreshed the page it was all of a sudden really easy to do the first time.
It'd also have been cool to have interactions with other numbers than the ambulance, I found it quite frustrating to dial another number and press the call button to have nothing happen and inevitably lose the game.
I also got quite frustrated by numbers lighting up as they do when you successfully press them but not be dialed
Anyway, good work!