In the game, Bibi with her baseball bat can knock around the giant Boss Robot.
In the investor video, you can see Boss Robot in the top left move a little as it's being worked on. We can use the worker near it as a rough estimate to its size. We know it's the Boss Robot, as the Investor Video is full of references to the game (basically 80/90% of it), and this robot has heavily similar shaped body to that of the Boss Robot. The Boss Robot is also the only huge machine in the game, so we can assume it is them.
Although the Investor Video has since been deleted due to legal contract issues, since they outsourced a production company, Frank, the game lead, confirms that all lore is canon to the game, and nothing has been retconned (besides Brawler descriptions from beta), especially the Investor Video in particular.
Height[]
The person here seems to be a woman. Starr Park is primarily run by Japanese. Japanese women are 158 cm tall. The woman is 470 pixels tall. 158/470 = 0.336170212766 cm per pixel.
The bottom leg of the Boss Robot is 516 pixels tall. 516 x 0.336170212766 = 173.463829787 cm tall.
An image of the Boss Robot's in-game model.
The same part of their legs is only 185 pixels tall. 173.463829787/185 = 0.937642323173 cm per pixel. We can now figure out the weight.
Weights[]
We can assume the Boss Robot is made of steel. Steel is primarily used by manufacturers for heavy duty machines, and given this video takes place several decades in the past, produced by a large corporation, we can assume they decided to use this material for their giant, not-for-commercial use mechs.
Steel weighs 7.9 grams per cubic cm. I'll hollow the light gray parts, but the dark gray parts that look like screws, shouldn't be hollowed, since screws are literally not hollow, and they appear more dense, which makes sense, they're like the skeleton for the robot.
Bottom Legs[]
We can safely guess that the radius is around half of its diameter, which seems to be half of its height.
Height is 173.463829787 cm. 173.463829787/2 = 86.7319148935 cm diameter.
86.7319148935/2 = 43.3659574468 cm radius.
Using Google's cylinder volume calculator, we get a volume of 1020000 cubic cm (the formula is automatically in cubic units). 1020000 x 7.9 = 8058000 grams. The Boss has 2 of these, so double it. 16116000 grams total. I doubt it's full though, so making it 80% hollow gives us total volume of 408000, which gets a weight of 3223200 grams.
Upper Legs[]
These are cylinders.
Height is 26 pixels. 26 x 0.937642323173 = 24.3787004025 cm tall. Length is 46 pixels. 46 x 0.937642323173 = 43.131546866 cm diameter. 43.131546866/2 = 21.565773433 cm radius. Use Google calculator, it's 35619.72 cubic cm. 35619.72 x 7.9 = 281395.788 grams. Double it since there's two, 562791.576 grams.
Pelvis[]
Cylinder.
Height is 131 pixels. 131 x 0.937642323173 = 122.831144336 cm tall. Length is 147 pixels, but it's a little curved, so I'll remove 1/4th of the length to compensate. Length now is 110.25 pixels. 110.25 x 0.937642323173 = 103.37506613 cm. 103.37506613/2 = 51.687533065 cm radius. Those results in a volume of 1030000 cubic cm. Half of this should be hollow, so 40%, which is 618000 cubic cm. 618000 x 7.9 = 4882200 grams.
Torso[]
Sphere.
Length is 380 pixels. 380 x 0.937642323173 = 356.304082806 cm. 356.304082806/2 = 178.152041403 cm radius. Using Google's sphere volume calculator, this should be 23700000 cubic cm volume. Assume 80% hollowness, and it's 4740000 cubic cm. 4740000 x 7.9 = 37446000 grams.
Shoulders[]
Ellipsoid... but I'm gonna call it a sphere. That would yield lower results, but I'm too lazy and that's easier.
Length is 154 pixels. 154 x 0.937642323173 = 144.396917769 cm. 144.396917769/2 = 72.1984588845 cm radius. Google Sphere calculator gets us 1580000 cubic cm. 80% hollow means it's 316000 cubic cm. 316000 x 7.9 = 2496400 grams. Two of them, resulting in 4992800 grams total.
Arms[]
Cylinder.
Height is 68 pixels. 68 x 0.937642323173 = 63.7596779758 cm tall.
Length is 59 pixels. 59 x 0.937642323173 = 55.3208970672 cm diameter. 55.3208970672/2 = 27.6604485336 cm radius. This results in a volume of 153000 cubic cm. 153000 x 7.9 = 1208700 grams. There's two arms, which means 2417400 grams total.
Hands[]
Cylinder.
Height of 130 pixels. 130 x 0.937642323173 = 121.893502012 cm tall.
Length is 115 pixels. 115 x 0.937642323173 = 107.828867165 cm diameter. 107.828867165/2 = 53.9144335825 cm radius. This results in volume of 1110000 cubic cm. 80% hollow means it's 222000 cubic cm. 222000 x 7.9 = 1753800 grams. There's two of them, which results in 3507600 grams total.
Total Weight[]
I'm not gonna do the head, since it would be very hard to guess how much is cut off by their large torso, and it wouldn't make much difference here anyway.
3223200 + 562791.576 + 4882200 + 37446000 + 4992800 + 2417400 + 3507600 = 57031991.576 grams in total, or 57031.991576 kg. (57031.991576 x 9.80665 = 559292.780189 kgf (Class K))
Speed + KE[]
Thankfully, KairosTime has a video of hitting the boss with Bibi, alongside a stopwatch.
The image showing the displacement.
From the pixel dimensions, the displacement (based off of the right of the Boss Robot's red circle hitbox) is exactly 1 and 2/3rds of a tile. The stopwatch within the video shows us it took 0.5 seconds for this to happen, making the Boss Robot's knockback speed 3 and 1/3 tiles per second (3.33333333333 tiles per sec).
Edgar, a Very Fast Brawler, moves at 2.73 tiles per second. This puts the knockback 1.221001221x faster than Edgar's travel speed. We know Very Fast Brawlers are 158.857142858 m/s. 158.857142858 x 1.221001221 = 193.964765394 m/s speed. (Subsonic+ knockback).
If we use the R-T signal speed from the same calc, 54612464.163 x 1.221001221 = 66681885.4248 m/s (Relativistic knockback).
The kinetic energy of a 57031.991576 kg robot moving at 193.964765394 m/s is 1072838209.9271 joules, or 0.256414486120243756 tons of TNT (Small Building level)
As for with the R-T radio wave scaling, the KE would be 126795629401430000000 joules, or 30.3049 gigatons of TNT, or Island level.
Everyone should scale since everyone can survive at the very least one Homerun swing from Bibi, most being able to survive several of them.