VERSUS MATCHES TROPHIES:
Winner
Win a versus match
Champion
Win 10 versus matches
Unstoppable
Win 100 versus matches
Start a 2-player versus match and change the settings to:
Time Limit: None.
Kill Limit: 1.
Regeneration: Off.
Continuous Play: On.
Choose the scene #7 - Meat Grinder. Now simply commit a suicide with second player by falling into the grinder on the bottom or walk into those on the sides. You will win 1:0, then simply start next match with 
(can be easily turboed).
"Champion" is glitched and it will pop after "Unstoppable" - you have to play ~15 extra matches.
Met Your Match
Finish 20 versus matches in a draw
Start a 2-player versus match and change the settings as mentioned above.
Choose the scene #7 with grinders. Now simply commit suicide with both players by falling into the grinder on the bottom or walk into those on the sides of the screen at the same time.
Even if "WINNER" will appear above one player, second one will be still crushed and the match will finish with draw.
FLESHBIRDS POPS TROPHIES:
Least Concern
Watch 10 fleshbirds pop
Near Threatened
Watch 100 fleshbirds pop
Vulnerable
Watch 200 fleshbirds pop
Endangered
Watch 500 fleshbirds pop
Critically Endangered
Watch 1000 fleshbirds pop
For those you have to see ANY fleshbird popping (exploding while dying) which means every "pop" which will appear on the screen counts - can be frag gotten by you, suicide or frag achieved by CPU, etc.
Simply start 8-players game, (1 player and 7 CPU - you do not have to change the CPU skill), change the settings to
Lives: Unlimited.
Powerups: None
Time Limit: None
Kill Limit: None
Regeneration: Off
Choose the scene #7 - Meat Grinder and... sit down and wait. You can block your 
to also commit suicide with your character and speed up the process a bit or try to work on mutator trophies.
Birds will almost constantly fall into "grinders" popping while dying.
SURVIVAL MODE TROPHIES:
Survivor
Clear 10 waves of cronenbirds in survival mode
Hunter
Clear 20 waves of cronenbirds in survival mode
Exterminator
Clear 50 waves of cronenbirds in survival mode
Choose Survivor mode and change settings to:
Lives: Unlimited.
Powerups: Very Frequent
Regeneration: Supernatural
Mutator duration: Permanent or very long
Start 8-players game (1 player and 7 CPU - set up CPU skill to max). Select area #1 - Hypodermic Hill. Your goal is to survive 50 waves of enemies (there is like... 2-7 per round). Since you have unlimited lives, very frequent mutators (permanent or very long) CPU can actually do the whole thing for you. You can sit back and wait until wave 50 or get some kills by yourself while working on the MUTATORS trophies in the same time.
SCENE SPECIFIC TROPHIES:
For all the below mentioned trophies, simply start 2-players VS game and select the right level:
Tenderised
Die to a swinging hammer
Select scene #3 - Cave Ruins with the swinging hammer and get killed by it.
Fresh Mince
Fall into a meat grinder
Select scene #7 - Meat Grinder and walk into one of them.
Rolling pin
Get popped by a rolling spike ball
Select scene #9 - Teleport Tunnel and get killed by rolling spike ball.
Beam Me Up!
Jump through a teleporter
Same scene as above - there is a teleport in the bottom left corner of the level, just get into it and die.
Tetanus
Die to the needles in the hypodermic stage
Select scene #1 - Hypodermic Hill and get killed by the moving spikes in the middle.
How Did You Get Up There?
Die to ceiling Spikes
Same scene as above - get the "FLY" mutator or be airborned by popped enemy and hit the spikes on the ceiling. Stay on them until you are dead.
Shoulda Looked Up
Get squashed by a holo-cube
Select scene #8 - Danger Room and get squashed by falling cube.
Cooperation makes it happen
Defeat a cronenbird in VS mode
Select scene #11 or #12. In the center there are cronebirds, same enemies which you have to kill in "Survival" mode.
Simply kill them all.
MUTATOR TROPHIES:
Mutators are powerups in this game. They look like shiny orbs and seems to be totally random. They give you an additional abilities (flying, shooting, extra speed, multi spike, etc.).
Set the rules:
Mutation Duration: Permanent
Powerups: Very frequent
Everything can be obtained in 2-players versus mode. Probably you got some of them already during Survival.
I think the "easiest" scene to catch a lot of mutators while not being disturbed by the "environment" is level #1 - Hypodermic Hill, but feel free to select another one if you feel more comfortable.
Mutated
Pick up any powerup
As simple as that 
.
Attack helicopter
Pick up the wings and beak gun powerup at the same time
A bit of luck is needed to have those same two mutators ("FLY" and "BEAK GUN") at the same time, but with rule "Permanent Mutation" every mutation will stay, so just keep getting the powerups until you will combine those two.
Centipede
Pick up multiple legs powerups at once
With "permanent" rule you will keep all the mutations, so continue to collecting them until you will pick up
"MORE LEGS" mutator three times.
Danger ball
Get a kill while you have no legs
The only "tricky" one. Mutator "NO LEGS" or "SITTING DUCKS" has to be collected by SECOND player, which will remove the "legs" of Player 1. You can not move then with Player 1, so walk quickly with P2 to P1 and got stabbed to death before your legs will reappear (those mutators are not affected by "permanent" setting).
What doesn't kill you
Block a spike with a tumor
Simply pick up "TUMOR" mutator and let enemy/2nd player stab you.
PLATINUM! :]
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