In an ideal world I think I'd have the tutorial be more integrated into the game - so the first time you find a weapon it tells you how to fight etc.
It's interesting that you didn't have trouble with the zombies - I spent hours on the last day trying to rebalance it and felt I had left it too difficult - maybe not!
Crafting is almost entirely non functional - you can use it to repair stuff and for one or two simple recipes and for one recipe used in the storyline - and that's it. I just ran out of time to add sufficient depth to it to make it interesting. Definitely something I'll revisit.
Thanks for playing and for the feedback :)