Just for the lulz, I want to get some Legend of Zelda CD-i profiles made. I'm gonna use two methods for calcing Link's bomb, one for the pulverization of the boulder, and one for the radius of the explosion.
The explosion happens at around the 1:05 mark.
Method 1: Destruction
Link is 68 px high and the boulder is 54.
According to this, Link's height should be 5'8, or 172 cm.
172 / 68 = 2.5 cm per pixel
2.6 * 54 = 135 cm for the boulder's diameter, 67.5 for the radius
So the volume is 1.29×10^6 cm^3
For fragmentation (x8): 10,320,000 Joules or 2.4 Kilograms of TNT - Wall level+
For V. Fragmentation (x69): 89,010,000 Joules or 27.3 Kilograms of TNT - Small Building level
For pulverization (x214.35): 276,511,500 Joules or 66.1 Kilograms of TNT - Small Building level
Method 2: Airburst RadiusLink's sword is 34 px long and the radius of the explosion from the point where the bomb was initially placed is 256 px.
I'll assume 85 cm for Link's sword.
85 cm / 34 * 256 = 640 cm, or .0064 km.
For the airburst formula: Y = ((x/0.28)^3)/1000 Y = yield in megatons x = radius in km
((.0064/0.28)^3)/1000 = 1.1941691e-8, or 1.2 Kilograms of TNT - Wall level