Thank you for the feedback! I really does lack real challenge as the challenge there is only in assuming that it is there. Technicaly there's no way to lose - I just did not implement that due to not wanting people to rage quiting my game after restarting the whole day :)
But there is some kind of way to lose because for example if you miss call about Gas leak - there will be another about Gas explosion and there's a lot of that kind of chains of missed calls. But they are practicaly hard to get as when these calls occur - you guaranteed to have a machine for that.
Checked out your game and commented it on your page :)