This guide should give a clear overview of what is required to earn all of the achievements in Revenge of the Titans. I was actually surprised that there wasn't already a guide for this great game. As a huge fan of the tower defense genre, I decided to take the task of compiling a guide upon myself.

The achievements in this game aren't actually that hard to get. However, I will also provide a few general gameplay tips that may help you with completing the campaign itself.

Many achievements are a lot easier to earn in Endless mode rather than in the campaign. I've noted them accordingly.

• The difficulty of each level automatically adapts to the amount of resources you have at the start of the level as money carries over from level to level. More starting money means that you will encounter stronger enemies. In addition, crystal patches are placed further away from your main base and there aren't as many of them, so plan accordingly.
  
  
• You can't effectively direct or "maze" the enemies because they don't follow a strict path. They also attack any buildings in their way and some enemies actively seek out stray structures such as remote refineries. It's therefore best to choose a single suitable choke point and defend it with all your turrets. Alternatively, you can just surround your base building with defenses and wait for the enemies to come to you.
  
  
• The research tree is mostly trial-and-error, so feel free to respec often. Most Technologies are prerequisites for other research, with a few exceptions. By clicking on a research option, you will see the passive effects it grants, if any. For example, Xenobiology increases turret damage, Nanohardening increases turret armor, etc. It's usually a good idea to focus on Applied Technologies, as most of them grant very useful passive bonuses to all your turrets.
  
  
• Most Delivery research options provide a one-shot bonus to your resources and are largely not needed, except as prerequisites. Other research that can be skipped easily include barricades, droid factories, heavy weapons and most miscellaneous buildings. While they all can be extremely useful in certain situations, it's best to focus on other research first and then experiment with whatever suits your playstyle best.
  
  
• Focus your building research on all six turrets, all five add-ons and the Capacitor. Other refining buildings and upgrades are certainly useful but not as vital as it might seem, especially early on. Basic mines are very useful once you've researched improved blast damage and range. Other mine types are situational, but also quite effective.
  
  
• Learn the hotkeys for all your buildings. It will save you a lot of time in setting up your defenses, adding new turrets during the game and replacing lost turrets in critical moments. Remember that "Q" zooms to your base, "E" zooms to unrefined crystals and "TAB" fast forwards the game by a considerable margin.
  
  
• If you want to make a profit on a level, avoid losing turrets or letting them get damaged. Each building is recycled at the end of the level for 40% of its cost. Damaged buildings are recycled at further reduced cost. Destroyed buildings and those that have a single hit point remaining don't refund anything at all.
  
  
• Earning bonuses at the end of the level is a good way to rack up money. You will receive substantial bonus cash if you don't let a single building get damaged. Other bonuses include not losing a single building (gives less cash than the first one) and harvesting all the crystals on the map (often unfeasible). Your base can also provide up to $1000 if it remains undamaged throughout the level.
  
  
• It's often not a good idea to attempt harvesting all resources on the map. Remote refineries are very vulnerable and may fail to turn a profit, especially in shorter levels. It takes 45 seconds for a single refinery to start turning a profit, assuming that the refinery isn't damaged. Remaining resources are automatically harvested at the end of the level at 10% efficiency, rounded down. For example, $1780 worth of resources remaining on the map at the end of the level are converted into $170.
  
  
• For a basic mid-game strategy, a handful of turrets (5-10) backed by about 15-20 add-ons are enough to hold virtually any position. In the early game, it's preferable to use basic Blasters and Heavy Blasters as your main turrets. Once you unlock Multi-Blasters and Blast Cannons, these two can weather almost any threat. The two advanced Cannon turrets are powerful, but you could actually beat the campaign without using either. They do make the process easier, though.
  
  
• Use the Capacitor! In my opinion, it's the best turret in the game. It's also the only turret that you must fire manually. The Capacitor has limited charge, which is improved by the Battery add-on and constantly replenishes itself. The Reactor add-on and Ionisation Laser upgrade can improve its range substantially. Capacitors can target invisible enemies, fully pierce any enemy armor, stun enemies on hit and quickly shoot down fliers. What more can you ask for?

With all that out of the way, let's get down to business!

BASTION

Defeated a Megatitan

Self-explanatory. The Megatitan first appears during the last level of World 1 (Earth). You will occasionally encounter other Megatitans in later levels.

PROTECTOR

Destroyed a Leviathan

Self-explanatory. The Leviathan first appears during the last level of World 2 (Moon). You will occasionally encounter other Leviathans in later levels.

DEFENDER

Destroyed a Gargantuan

Self-explanatory. The Gargantuan first appears during the last level of World 3 (Mars). You will occasionally encounter other Gargantuans in later levels.

STALWART

Destroyed a Behemoth

Self-explanatory. The Behemoth first appears during the last level of World 4 (Saturn). You will occasionally encounter other Behemoths in later levels.

SLAYER

Destroyed the Ultratitan!

Self-explanatory. The Ultratitan only appears during the last level of World 5 (Titan).

EARTH COMPLETE

Completed the Earth missions

Awarded for completing levels 1-10.

MOON COMPLETE

Completed the Moon missions

Awarded for completing levels 11-20.

MARS COMPLETE

Completed the Mars missions

Awarded for completing levels 21-30.

SATURN COMPLETE

Completed the Saturn missions

Awarded for completing levels 31-40.

TITAN COMPLETE

Completed the Titan missions

Awarded for completing levels 41-50.

PERFECT GAME

Completed all missions at maximum difficulty

Awarded for completing the campaign. Simply start the campaign and never choose the option to "generate easier level". You get a gold medal at the end of each level. The achievement is awarded once you have all 50 gold medals. There are no other conditions for earning a gold medal other than simply surviving the level.

PERFECT WORLD

Completed whole world at maximum difficulty

Awarded for earning 10 gold medals in a single world (there are five worlds total, each with ten levels). The achievement should be awarded after completing the first one (Earth).

CARELESS

Lost 10 buildings to the enemy

See "NEGLIGENT".

RASH

Lost 25 buildings to the enemy

See "NEGLIGENT".

RECKLESS

Lost 50 buildings to the enemy

See "NEGLIGENT".

NEGLIGENT

Lost 100 buildings to the enemy

Self-explanatory. Everything you can build (other than mines and barricades) will count towards this total. Should come naturally during the campaign.

VANQUISHED 100

Vanquished 100 Titans

See "VANQUISHED 10000".

VANQUISHED 250

Vanquished 250 Titans

See "VANQUISHED 10000".

VANQUISHED 500

Vanquished 500 Titans

See "VANQUISHED 10000".

VANQUISHED 1000

Vanquished 1,000 Titans

See "VANQUISHED 10000".

VANQUISHED 2500

Vanquished 2,500 Titans

See "VANQUISHED 10000".

VANQUISHED 5000

Vanquished 5,000 Titans

See "VANQUISHED 10000".

VANQUISHED 10000

Vanquished 10,000 Titans

Self-explanatory. Every killed enemy will count towards this total. 5000 kills should come naturally during the campaign and 10,000 kills can easily be reached in Endless mode.

CRUSHER

Crushed 25 Titans under new buildings

See "DIMENSIONAL TRANSGIDRIFIER".

SQUISHER

Squished 50 Titans under new buildings

See "DIMENSIONAL TRANSGIDRIFIER".

DIMENSIONAL TRANSGIDRIFIER

Turned 100 3-D Titans into 2-D Titans

Since you can place your buildings anywhere, you can actually use them to instantly kill enemies. Just place a building on top of an advancing enemy. The achievement is awarded for 100 kills. Easily earned in Endless mode.

SIZZLE SIZZLE

Fried 100 Titans with the Capacitor

See "KRISPY KREME".

SAUSAGES AND BACON

Fried 250 Titans with the Capacitor

See "KRISPY KREME".

KRISPY KREME

Fried 500 Titans with the Capacitor

Once you research the Capacitor turret, you can build and use it to manually target and kill enemies. The achievement is awarded for 500 kills. Easily earned in Endless mode.

DEATH FROM THE SKIES

Nuked 50 Titans from orbit

See "AUTHOR OF ARMAGEDDON".

BRINGER OF THE APOCALYPSE

Nuked 100 Titans from orbit

See "AUTHOR OF ARMAGEDDON".

AUTHOR OF ARMAGEDDON

Nuked 250 Titans from orbit

Awarded for using the Smartbomb power-up to kill a total of 250 enemies. Easily earned in Endless mode.

BOOM!

Blew up 100 Titans using explosives

See "BLAM!".

KABOOM!

Blew up 250 Titans using explosives

See "BLAM!".

BLAM!

Blew up 500 Titans using explosives

Awarded for using mines and/or rockets to kill a total of 500 enemies. Easily earned in Endless mode.

OFFENSIVE CAPABILITY

Researched all weapons

Awarded for researching all ten weapon types (the six turrets, three heavy weapons and the Capacitor).

DEFENSIVE CAPABILITY

Researched all defenses

Awarded for researching all four barricade types, plus the Shield Generator.

SPEAR AND MAGIC HELMET

Researched all turret upgrades

Awarded for researching all five turret add-ons, plus all four turret stat upgrades (Ionisation Laser, Lithium Concentrator, Liquid Sodium Cooling and Precision Mechanisms).

DANGEROUS NUTTER

Researched all explosive tech

Awarded for researching all three mine types, plus Rockets and Plastic Charge Patterns.

ROBOT WANTS KITTY

Researched the droid factory

Slightly misleading description. Awarded for researching all three factory types, plus the Advanced Battledroids upgrade.

PROPELLERHEAD

Researched all science and technology

Awarded for researching all basic, advanced and applied technologies.

A PROBLEM FOR OUR GRANDCHILDREN

Researched nuclear reactors

Awarded for simply researching the Reactor.

DEVIOUS

Researched the decoy tower

Awarded for simply researching the Decoy.

ENCYCLOPAEDIC

Researched everything

Awarded for researching all buildings and technologies. Due to the limited number of available research choices in the campaign, this can only be earned by playing the Endless mode. Note that researching the items in the "Deliveries" category is not needed, other than as prerequisites for other technologies.

TAPE AND STRING

Base held together with tape and string at end of mission

Awarded for surviving a level with only one hit point left on your base building. Easily done as early as in the first level by letting the first handful of enemies through and then placing your turrets.

PHEW! THAT WAS CLOSE

Giant Titan killed within a few metres of the base

Awarded for killing one of the boss titans while he's near your base. Easily done in the last level of World 1 (Earth - Minsk). When the Megatitan appears, place enough turrets next to his path to reduce his health to about a quarter (about 2-3 Multi-Blasters should be enough). Once he's close enough to your base, use a Smartbomb to kill him instantly.

SKIN OF YOUR TEETH

Lost 90% of your buildings to the enemy

Awarded for surviving a level after losing over 90% of your buildings. Easily done in the eighth level of World 1 (Earth - Kiruna). Simply keep placing cheap (non-turret) buildings on the path of advancing enemies. Since damaging your buildings also kills the enemies, you can basically use your buildings as landmines (actual mines don't count as buildings for the purposes of this achievement). If done correctly, you should have no buildings left once all the enemies are dead (other than the base, of course).

AWESOME

Fully upgraded a turret

Awarded for surrounding a turret with the maximum number of active add-ons. Easily done in any level once you've researched all five different add-ons. During the build phase, simply place a single turret and surround it with four of each add-on, for a total of 20 connected add-ons.

SHORT TEMPERED

Used bezerk powerup 5 times

Awarded for using the "Bezerk" power-up a total of five times. Easily done during the campaign.

THE ONLY WAY TO BE SURE

Nuked the site from orbit 5 times

Awarded for using the "Smartbomb" power-up a total of five times. Easily done during the campaign.

TOILET BREAK

Used the freeze powerup 5 times

Awarded for using the "Freeze" power-up a total of five times. Easily done during the campaign.

MR. FIX IT

Repaired your buildings 5 times

Awarded for using the "Repair" power-up a total of five times. Easily done during the campaign.

BATFINK

Used the shield powerup 5 times

Awarded for using the "Shield" power-up a total of five times. Easily done during the campaign.

THRIFTY

Made $5,000 profit from one mission

See "SHORT ARMS DEEP POCKETS".

TIGHT FISTED

Made $10,000 profit from one mission

See "SHORT ARMS DEEP POCKETS".

SHORT ARMS DEEP POCKETS

Made $15,000 profit from one mission

Awarded for accumulating at least $15,000 profit in a single level. Very difficult to do in the campaign, very easy in Endless mode. Basically, you need to finish the level with at least $15,000 more than you started it with. The best way to achieve this is during a level in which you receive the medal for 5000 or 10,000 kills, because the medal bonus of $5000 counts towards your profit goal and makes the task far easier. These medals are awarded both in campaign and in Endless mode, so you have four attempts at this method. Note that you can also replay these levels and trigger the medal again should you fail. It's also best to play on a level where you have low initial cash, because more starting money means less crystal on the map, which means fewer mining possibilites and less potential profit. You can also reset the level to generate an easier map, which usually means that crystal is concentrated nearer to your base and therefore easier to gather. Any harvesting speed upgrades and/or strategically placed Collectors will help you immensely. Note that earning the achievement for accumulating $15,000 profit will award you the other ones as well.

HOARDED $5000

Got $5,000 in the bank

See "HOARDED $50000".

HOARDED $10000

Got $10,000 in the bank

See "HOARDED $50000".

HOARDED $25000

Got $25,000 in the bank

See "HOARDED $50000".

HOARDED $50000

Got $50,000 in the bank

Awarded for accumulating a cash reserve of at least $50,000. Easier to attempt in Endless mode because the game's difficulty scales with the amount of money you have. Therefore, attempting this achievement while playing the campaign can make the levels quite difficult. Endless mode is actually much easier than the campaign, as you can generate easier levels with weaker enemies and more favorable crystal placement. Just don't let your buildings get damaged or destroyed, harvest safe crystal patches and pick up cash drops. You should reach $50,000 with almost no trouble.

WARRANT OFFICER

New rank: warrant officer

See "FIELD MARSHAL".

SECOND LIEUTENANT

New rank: second lieutenant

See "FIELD MARSHAL".

LIEUTENANT

New rank: lieutenant

See "FIELD MARSHAL".

CAPTAIN

New rank: captain

See "FIELD MARSHAL".

MAJOR

New rank: major

See "FIELD MARSHAL".

LIEUTENANT COLONEL

New rank: lieutenant colonel

See "FIELD MARSHAL".

COLONEL

New rank: colonel

See "FIELD MARSHAL".

BRIGADIER

New rank: brigadier

See "FIELD MARSHAL".

MAJOR GENERAL

New rank: major general

See "FIELD MARSHAL".

LIEUTENANT GENERAL

New rank: lieutenant general

See "FIELD MARSHAL".

GENERAL

New rank: general

See "FIELD MARSHAL".

FIELD MARSHAL

New rank: field marshal

Awarded for reaching a score of 50,000 during the campaign or in Endless mode. The score can be increased by earning new medals. You should steadily progress through the ranks simply by playing the game. While it's quite possible to reach this score by the end of the campaign, it's more likely that you will need to play Endless mode to obtain the achievement.

There are five hidden achievements in the game that can only be earned in the Yeti Attack mode, which is available during the period of 19 December – 8 January. You can also simply change your computer clock's date to unlock this mode.

DISAPPOINTING PRESENTS

Defeated 1 Xmas Ultrayeti

See "DRUNKEN FAMILY ARGUMENT".

UNDERCOOKED TURKEY

Defeated 2 Xmas Ultrayetis

See "DRUNKEN FAMILY ARGUMENT".

NO-ONE LIKES XMAS PUDDING

Defeated 3 Xmas Ultrayetis

See "DRUNKEN FAMILY ARGUMENT".

SPROUT FLATULENCE

Defeated 4 Xmas Ultrayetis

See "DRUNKEN FAMILY ARGUMENT".

DRUNKEN FAMILY ARGUMENT

Hurrah! Christmas is finally over!

Awarded for completing the Yeti Attack mode by killing the five Xmas Ultrayetis. Yeti Attack is basically a small snow-covered extra map with a single enemy path, abundant resources, all buildings unlocked, and Yetis as enemies. This bonus mode should offer no challenge to anyone who's already completed the campaign.

That's it. I hope this guide has been helpful.

Thanks for reading and have fun playing!