It is possible to directly power ATTiny85  (power LED lights up). But any minimal slow down in turning the hand power generator  crank handle immediately resets the ATTiny85. I was never able to pass the initial 5s pause before sketch begins to run. I remembered step up boost converter  and gave it a try. As you can see I passed the 5s phase and the 2nd LED got lit, but then I was not quick enough and the ATTiny85 did reset. But after that and after another 5s pause the 2nd LED get on and off 5 times!
Here is the youtube video: