If reforms aren't being implemented, something else must be causing the Greek budget to contract by 34%.

That's a big contraction. I'm going to guess that they've put through a lot of reforms, salary cuts, budget cuts, etc.

Well no, it won't implement all the measures, because these measures will cause further contraction of the economy (never mind riots) and thus they will have to be "revisited" i.e. the troika will come up with even more outrageous cuts and societal destruction.
But this will pass from parliament (with losses) and they already started to implement it: larger classes at schools, 20000 families at least unable to find public nurseries for their children, hospitals turning away people, pay cuts for what used to be respectable (i.e. relatively high-paying) jobs to poverty levels etc.
The thing is that with every new package of measures the Greek economy is being seriously damaged, because it kills off an even larger part of its productive capacity and its infrastructure (such that it was). Greek society is in shambles, creating fissures that it will take decades to mend. Meanwhile pumped up by the media and government rhetoric (Samaras' government is easily the most xenophobic and right wing government anywhere in the EU, I reckon) the Nazi party (not metaphorically, literally) is going on murderous sprees against immigrants pretty much unimpeded, if not cheered, by the police.

So anything along the lines of what we already had (austerity on steroids) is deadly. Samaras was elected on the explicit promise that he will not implement the more outrageous of the demands and will forcefully renegotiate. He has not delivered, to put it mildly.

The road of excess leads to the palace of wisdom - William Blake