This is just from a quick google search, so if you have any other Easter Eggs, Glitches, unlockables, or Cheats... post them here.

Trophy/Achievement list (reprinted below)

Videos on gaining in-chapter trophies, and a cheat for another one.
(a "semi-cheat" - like WFC, if you complete the final chapter on "hard" (or most of it, as you can change the difficulty setting at any time), you will automatically earn the "Easy" and "Normal" trophies as well... if you aren't enjoying the game enough to play it twice more)

Video guides for obtaining all blueprints and audiofiles - Xbox, PS3, PC (note - all 3 pages use the same video files)
Another video guide for blueprints and audiofiles.
Text guides for obtaining all blueprints and audiofiles

Easter Eggs - Find Starscream's crown, Optimus' WFC axe, Arcee poster, MegaFun arcade, Grimlock's room, the dancing robot, Soundwave in his Gen1 pre-Earth mode, Super Grimlock (mario?) Quest 64 game, plus a few others listed on that page.

Unlockable items - the two weapons for completing the Campaign, and the Xbox exclusive "clothing" for their avatars (Optimus & Megatron helmets, and male and female HighMoon t-shirts).

A couple of glitches found so far, in campaign and multiplayer.


PS3 Trophy/Xbox achievement listing

Xbox - 50 achievements (1000 points)
PS3 - 51 trophies (1 platinum, 2 gold, 6 silver, 42 bronze)


Vector Sigma Victory (Platinum/NA) — Unlock All Trophies (not an Xbox achievement)

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Campaign (36)
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The Exodus (Bronze/10) — Complete Chapter I
Defend the Ark (Bronze/10) — Complete Chapter II
Metroplex Heeds the Call (Bronze/10) — Complete Chapter III
Eye of the Storm (Bronze/10) — Complete Chapter IV
Cut and Run (Bronze/10) — Complete Chapter V
Death from Above (Bronze/10) — Complete Chapter VI
Belly of the Beast (Bronze/10) — Complete Chapter VII
Combaticons Combine! (Bronze/10) — Complete Chapter VIII
Megatron Returns (Bronze/10) — Complete Chapter IX
The Final Countdown (Bronze/10) — Complete Chapter X
Starscream’s Betrayal (Bronze/10) — Complete Chapter XI
Grimlock Smash (Bronze/10) — Complete Chapter XII
Till All Are One – (Optimus Ending) (Bronze/15) — Complete Chapter XIII as Optimus
Till All Are One – (Megatron Ending) (Bronze/15) — Complete Chapter XIII as Megatron


The Battle is Far From Over! (Bronze/25) — Complete Campaign – Easy
More Than Meets the Eye (Silver/50) — Complete Campaign – Normal
All Hail You! (Gold/100) — Complete Campaign – Hard


The Last Stand (Bronze/15) — Chapter II: Save two Autobots when Optimus is downed by the first Leaper
Carnage in C-Major (Bronze/15) — Chapter III: Take out a cluster of five Decepticons using Metroplex’s Air Strike
Invisibility Spray (Bronze/15) — Chapter IV: Sneak through the Trash Compactor Facility undetected
Target Master 2.0 (Bronze/15) — Chapter V: Shoot a Sniper out of the air with a scoped weapon
Car Wash of Doom (Bronze/15) — Chapter VI: Destroy all of the homing mines chasing Blast Off before they self destruct
Club Con! (Bronze/15) — Chapter VII: Ram a jet (on the ground or in the air)
Fusilateral Quintrocombiner (Bronze/15) — Chapter VIII: Melee an enemy through the goal post
I, Robot Master (Bronze/15) — Chapter IX: Destroy all images of Starscream and his Statues
The Harder They Die (Bronze/15) — Chapter X: Kill five Autobots with a single hover slam attack
Internal Affairs! (Bronze/15) — Chapter XI: Hack all of the security terminals before the Decepticons can activate them
Slap the Grimlock (Bronze/15) — Chapter XII: Kill a Leaper in the air with an explosive barrel


Monacus Spender (Bronze/25) — Spend 250,000 Energon in the Teletraan 1 store
Reconstructor (Bronze/15) — Fully upgrade one weapon
Master Builder (Silver/25) — Fully upgrade all weapons
Teletraan 1 Regular (Bronze/10) — Rate all weapons, weapon upgrades, and equipment
Chop Shop (Silver/50) — Purchase all weapons and perks


Beachcomber (Bronze/25) — Collect all blueprints (note - need to find all blueprints to be able to earn 30, 31 & 32)
Cassetticon Audiophile (Silver/25) — Collect all audio logs
Octopunch Scavenger (Bronze/15) — Open fifteen Armory Recreators in Campaign or Escalation


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Multiplayer (9)
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Reconfiguration Matrix (Bronze/10) — Create a custom character in Multiplayer
Headmaster! (Bronze/25) — Reach max level in a single class
King of the Scrap Heap (Gold/100) — Reach max level in all four classes
What Prime Directives? (Silver/25) — Unlock Prime Mode
Full Throttle Scramble Power! (Bronze/15) — Earn MVP in any game mode during a public Multiplayer match
Ultimate Menasor (Bronze/15) — Capture three flags in a single CTF game during a public Multiplayer match
Moonbase One (Bronze/15) — Personally capture all 3 nodes in a conquest game during a public Multiplayer match
Ballistic Energon Goodie (Bronze/15) — Return five heads at once in a headhunter game during a public Multiplayer match
Heavy Metal War (Bronze/15) — Kill 6 different opposing players in a TDM game during a public Multiplayer match


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Escalation (5)
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Robotopossum (Bronze/15) — Complete wave 15 in Escalation (Ignition)
Maccadams Old Oil House (Bronze/15) — Complete wave 15 in Escalation (DownFall)
Space Pirates! (Bronze/15) — Complete wave 15 in Escalation (Oblivion)
Rust Marks (Bronze/15) — Complete wave 15 in Escalation (Ancients)
Ultra Power Master (Silver/25) — Spend 100,000 credits in Escalation