I try to put an emphasis on making progress through the game i.e. get to this point by the day or week. Sometimes I fall behind schedule because there might be a bit that causes more problems that I expected to, I usually get round this by putting in a little more work the next week in order to get to where I wanted to.
All this applies with the exception of my recent SM64 run since we knew all the improvements and had a few small ideas of our own. Easy I thought, 7-10 days of very hard work will get this finished. So I thought if I spend an average of 4 hours a day I'll easilly get this finished. Apart from the newer stuff was considerably more difficult to implement and optimize that I thought, heck we even redid areas just because one of us wasn't quite sasified with the camera angles, since I was under the impression that this
might be the definitive run, in the end it probaly took more like 33-35 days. So what I thought would take 30-40 hours ended up taking 130-140 hours.
So when you consider that there is about 5 mins of gameplay, do the the maths