Finished on first try, so I guess I got lucky. Indeed the randomness makes it a bit hard, but if you take your time it's not that bad since everything recovers with time (maybe with a timer it'd have been more challenging/frustrating ^^). There was a vending machine that was overcrowded, but since it was the last one I just sprinted to it and won before losing all patience.
In short, pretty fun game all things considered. I've seen other similar games fail horribly at some things which you got right (zoom, enemy field of view, etc.).