Lots of stuff here, from attack potency to speed, and even values for Size Manipulation.
Cuphead/Mugman Height[]
Before I can accurately measure the following feats, I'll need an exact height estimate for both Mugman and Cuphead. Luckily, there's someone we can compare them to.
She has pale skin, so we'll assume her to be a white woman. The average height in that regard is 64 inches, or 1.6256 meters.
Cuphead is crouching a little bit here because he's shooting, but Mugman is also crouching in the other calcs regarding AP, and since they're comparable this should be fine.
Cuphead while crouching is 132 px, and the lady is 306 px at 1.6256 meters, so he's 0.7012392156862745 meters tall.
Mugman and Sleeping Rock-Lion in Metamorphic Mess![]
Feat happens here. Cuphead and Mugman can both destroy this rock lion. This is late game.
I'll be calculating its destruction while lying down, because while roaring it has the shape of a "small stellated dodecahedron," which I have no idea how to calc.
We'll be using a sphere's volume formula, since it appears this way while lying down, the rocky "mane" of sorts would form this shape when retracted, and there's no exact way to calculate this shape, since it doesn't follow a consistent pattern you can measure like any sort of polygon.
The rock lion is 212 px while lying down, and Mugman (like Cuphead) is 105 px at 0.7012392156862745 meters tall when crouching, so the rock lion must be 1.415835368814192 meters in diameter, or 0.7079176844070962 meters in radius, which in turn makes it 148.60618797806 cm^3.
Typically, we use pulverization when we can't see anything left after something is destroyed, but the rock lion also turns into a puff of air before fading away. This can be seen as a simple special effect however, so we'll do a low-end and a high-end. Also, given that rocks are tightly compressed, we'll factor in the compressive strength for our answers.
The type of rock found in mountain sides (where this lion is) is metamorphic, and metamorphic rock is formed when existing rock is chemically or physically modified by intense heat or pressure. The pressure exerted upon it gives it a compressive strength of 10 to 50 to 100 MPA. Igneous (high grade) metamorphic rocks can even reach an MPA of 200, but igneous means formed by lava or magma, and if that were the case then the cracks we clearly see in this rock-lion would be smoothed over, so at best it's 100 MPA.
We'll do a low-end of 10, a mid-end of 50, and a high-end of 100 MPA.
Pulverization[]
Pulverization of rock is 214 j/cc.
Low-end: 318017.2422730484 J. Wall level
Mid-end: 1590086.211365242 J. Wall level+
High-end: 3180172.422730484 J. Wall level+
Vaporization[]
Vaporization is typically 25700 j/cc.
Low-end: 38191790.31036142 J. Small Building level
Mid-end: 190958951.5518071 J. Small Building level
High-end: 381917903.1036142 J. Small Building level
Note that the MPA for metamorphic rocks is determined by the grade, whereas high grades are 100 to 200, average grades are 50 to 100, and low grades (typically asigned to rocks smaller than our rock-lion here) are 10 to 50. Given that our rock-lion isn't exactly small and is nearly the size of a human while laying down, it's not a low grade, so the low-ends for both the pulverization and vaporization methods are unusable.
Similarly, with something of such a great size (keep in mind it's nearly the size of a human laying down, greater than a human in size when roaring and still laying down, and likely twice the size of one while standing on all fours) that easily rivals boulders, it's hard to imagine that average or intermediate metamorphism would fully form such a beast.
Tl;dr, low-ends are unusable, mid-ends are very doubtable, and the high-ends are the most likely.
Also, the puff thing happens to enemies like the Acorn Maker, which as shown later, get violently fragmented. It's just a special effect. Vaporization is unusable.
Thunder... thing.[]
Feat happens here... sorta. Cuphead isn't actually shown dodging the lightning here, but it comes down out of the guy's mouth gradually. In fact, if you look at the frames, you can see it coming out over time. Now, I can't show you directly Cuphead dashing away from the electricity, because I don't have a video where someone does that. However, I can prove to you theoretically that he can dodge it.
For the following we'll be assuming 30 frames is a second since that's what I rendered it in.
Here's a comparison of Cuphead's crouch to his standing pose. Crouching, he's 0.7012392156862745 meters at 38 px. Standing, he's 39 px, so he's 0.7196928792569659 meters. In these 7 frames, he can dash 95 px, or 1.753098039215686 meters. In a speed = distance*time calculator, this gets a result of 11.8575 m/s.
Now this guy. The lightning monster man's lightning can travel 518 px, or 2.84580848439014 meters. In a speed = distance*time calculator, this gets a result of 14.229 m/s. However, lightning is of course higher than that. 440,000 m/s to be exact. While the 14.229 result is inaccurate, we can use it to cross-multiply and find out how fast Cuphead travels in comparison.
440000 = 14.229
366,666.67 = 11.8575
Cuphead thus travels at 366,666.67 m/s, or 0.1223068360178694% the speed of light. Massively Hypersonic+
Cuphead and Gruff McLobster in Lightning Leap![]
Feat happens here. Cuphead jumps this lobster's lightning bolt.
Cuphead is 109 px, distance is 356 px, he jumps 305 px.
Distance he moved: 2.013819524526372 meters
Distance the bolt was from him: 2.350556559775045 meters
(2.013819524526372) x (440000) / (2.350556559775045) = 376966.2921348305 m/s. Massively Hypersonic+
Nuke-Head[]
Feat happens here. Cuphead can become a big nuke, and make a big explosion. This happens in every part of the game.
Cuphead here is 100 px standing, and his head is 49 px. Thus, his head is 0.3526495108359133 meters.
Airplane-Cuphead's head is 37 px, and the explosion is 381 px. Thus, the explosion is 3.631336854823864 meters. Halved for the radius is 1.815668427411932 meters.
Formula is ((radius/.28)^3)/2 = grams in tnt.
((1.815668427411932/.28)^3)/2 = 136.3344264525273 grams of tnt. 0.00015028298034700990609 tons of tnt. Wall level
Acorn Maker[]
Feat happens here. Cuphead destroys this big acorn-making machine. This is early game.
Cuphead is 106 px, the acorn maker is 378 px. Cuphead is shooting, so we'll use his crouching height of 0.7012392156862745 meters. Because of the shape of the acorn maker, we'll use a cylinder and two cronical frustums for the volume.
Cylinder = 267 px height (1.76632896781354 meters), 193 px for top base (1.276784609692934 meters, halved for radius is 0.6383923048464669 meters), total volume is 226.15008272017 cm^3.
Bottom cronical frustum = 58 px height (0.3836969293377728 meters), 158 px for bottom base (1.045243359230485 meters, halved for radius is 0.5226216796152423 meters), 70 px for top base (0.4630825009248983 meters, halved for radius is 0.2315412504624491 meters), total volume is 17.991015859291 cm^3.
Top cronical frustum = 33 px for height (0.2183103218645949 meters), 73 px for bottom base (0.4829288938216796 meters, halved for radius is 0.2414644469108398 meters), 136 px for top base (0.899703144654088 meters, halved for radius is 0.449851572327044 meters), total volume is 8.4425946092908 cm^3.
Adding this all together, the final total volume is 252.5836931887518 cm^3.
Factory machines are typically made of steel. We'll use the average violent fragmentation value as a low end, then the steel violent fragmentation value as a high end.
Average violent frag: 17428.27483002387 J. Wall level
Steel violent frag: 143593.8295778054 J. Wall level
Shots-Head[]
Get it? As in shotglass?
This is just calculating the size of Cuphead in his airplane when he shrinks.
Cuphead's head is 36 px, which is 0.352649510835913 meters.
Airplane Width: 0.1861205751633985 meters
Airplane Height: 0.2840787726178188 meters
Airplane Length: 0.6857073821809419 meters
Total airplane volume is 3.6255340968203 cm^3. 3 cubic centimeters. Sweet.