As touched on here, here and here I too think there is an issue with the drop rates of the mats and/or the recipe costs.

1) Abandoning the mission at the first set of loot boxes essentially gives you next to no material rewards - whats the point of it?
2) Playing on normal difficulty appears to make 5* giftwrap inaccessible - so without the 5* material then all the others serve no purpose.
3) The drop rate and costs of materials seems to be 'bad' for 2 reasons: two different kinds of 3* and 4* material; and disproportionately high consumption of those materials compared to the 5* giftwrap.

At the time of writing I have:
105 coal
95 treats
84 stockings
99 ribbons
27 giftwraps

So I'm about half way to making a sword or gun - as far as the 3*/4* mats are concerned anyway. By the time I get enough to do that I will have about 4 or 5 times the required amount of 5* mats. The bombs are cheaper to make due to diverse 4* material costs and the poison bomb is even cheaper still due to diverse 3* costs. That being said, if I make the fire bomb when I have enough 3* mats, then the consumption of the 4* mats will prevent me from making a sword or gun at that time - ironically I won't then be able to make the freeze bomb due to consumption of 3* mats...

Recommendations:
Merge all coal and treats into 1 unified 3* material.
Merge all stockings and ribbons into 1 unified 4* material.
Half the costs of the 3* material to 100 units.
Half the cost of the 4* material to 75 units.
Make 5* material accessible in normal difficulty.
For aborting the mission early after the first round, then "use it or lose it" - either add more mat drops, or totally remove them.

As it stands due to the separate 3*/4* materials and quirky recipe costs, we will end up seeing a lot of Humbug Hazers about, but not much else.

>inb4 responses about how rare things are suppoooosed to be rare