the result is:

0

-2

-3

-4

-5

-6

...

at each tick it adds -1 to the z-velocity, G = 1 is the acceleration based on tick (1/35) and unit, to translate it to meters and seconds, some substitutions have to be done:

G*(m/s*s) = 1

1meter = 32units, 1second = 35ticks

G*(32/35*35) = 1

G = 35*35/32 = 1225/32 = 38.28125 (in meters/second^2)

so the doom Gravity=1.0 is more than Earth gravity in x3.9 times.

After 1 second of falling from a standstill, a typical gravity 1.0 actor will be falling at a speed of 35 units per tic.

This translates to 35x35 units per second - 1225.

35 units per second, and the second is 35 ticks, so it's 1 unit per tick.

Is Doom's gravitation acceleration really up to four times what we see in real life!?

yes, 38.28125/9.8 = 3.90625 a bit more precisely.

those are my calculations, maybe wrong somewhere, but i've made some projectile fall tests from 10 meters (320units) and it looks and feels quite natural with the g=9.8