https://imgur.com/a/PDjOJ4m (There is one unmarked grass tile in the bottom right)
It appears that there are in total
27+21+22+
30+68+82+
185+30+96 = 561
brick wall tiles and
39+56+101+
28+62+45+
0+58+34 = 423
grass tiles. These total to 5472 hunger.
In addition to these, there are
33 tier 1 gems, 4 tier 2 gems, 1 tier 3 gems, 3 tier 4 gems, 6 tier 5 gems, 1 tier 6 gem, 2 gems of tier 7 and 8 and 1 more of tiers 9 through 12.
When we merge gems we get the following payouts
1,2,4,8,14,23,32,41,50,... and so on, increasing by 9 for each subsequent tier. Therefore, as the brick walls merge into tier 5 gems, we should receive
(423+33)/2 = 228; (228+4)/2=116; (116+1)/2=58; (58+3)/2=30; (30+6+423)/2=229; (229+1)/2=115; (115+2)/2=59; (59+2)/2=30; (30+1)/2=15; (15+1)/2=8; (8+1)/2=4; (4)/2=2; (2+1)/2=1.
The payouts are thus 228*1+116*2+58*4+30*8+229*14+115*23+59*32+30*41+15*50+8*59+4*68+2*77+86=11635. Substracting the hunger, we should be able to get 6163
