The Beast: MDM is a series of quicktime challenges, in which you kill a bunch of people. You can do the regular murders with the spacebar when the word KILL shows up, or secondary murders with M (for Madness). Since everything is always the same, here's everything you need to know to get all the medals:

Medals (14 for 220pts):

Obtained by killing people with space bar:
Censored in Beast Trilogy (5) - Rip the first dude's head off.
Have A Nice Day (5) - Perform The Beast's signature smiley fatality.
Axe-cuse Me (5) - Beat the shit outa the A.T.P. agent with your axe.
Friends Stick Together (10) - Execute Sanford and Deimos with a shotgun.
Balls!! (10) - Crush Mag Agent, Torture.
Cruci-fuck You! (25) - Collect the heart of Jesus.
I... Hate... Clowns!! (50) - Explode Tricky's skull.

Obtained by killing people with M:
Where Is My Strawberry Tart? (5) - Shotgun rape the first guy.
He Didn't Have The Guts (5) - Remove the Sheriff's organs.
And It Was All Yellow (5) - Beat the shit outa your axe with the A.T.P. agent.
Boom! Shake-shake-shake The Room! (10) - Show Sanford and Deimos your grenade collection.
Cus He Had Nobody To Go With. LOLOL! (10) - Steal the mag agent's skeleton.
You Aint Got No Pancake Mix! (25) - Tear Jesus a new one.
Yoink (50) - Practice a bit of brain surgery on Tricky.

Key patterns to win:
r = right
l = left
u = up
d = down
kill = spacebar or M
Letters in sequence are part of the same command, and must be done in sequence quickly (i.e. lr = left then right, quickly)
Letters above each other are different commands

First Dude:
r
kill

Sheriff:
l
l
l
l
r
kill

The Weapon:
d
u
d
u
d
u
d
kill

The Comrades:
u
rd
l
rl
r
ll
kill

The Monstrosity:
d
urd
ll
r
r
u
l
kill

The Savior:
r
lr
dd
rr
du
u
rr
kill

The Clown:
l
(he transforms)
lr
rl
rlr
ldr
drul
urur
durd
dldlu
m