As a Level Designer on Fallout 3, I was responsible for the layout, enemy placement and behavior, loot placement, puzzles and overall theme and background of various places within the game. I also was responsible for the traps system, including scripting the traps and working with artists, programmers and others to get the traps functioning in-game.

Locations of Note:
Here are a few places that I'm particularly proud of.

Mobile Base Crawler
This area consists of the last four combat sections the player goes through on the extended main quest of Fallout 3.

The first area is the crawler's underbelly, where the player encounters Stiggs, an Enclave engineer. You can extract information from him, and either choose to kill him for siding with the Enclave, or let him go after hearing his side of the story. With the right perk, you can learn how to turn all of the robots in the base against the Enclave by accessing the robot control mainframe in the next area.

The second area is the crawler's main part, containing the control room, dorms, a med bay, a deathclaw research station and an armory. In this area you can unleash a friendly deathclaw that will massacre Enclave personnel, find tons of loot in the armory, and gain access to the top part of the platform.

The third area is the top of the platform, occupied by some of the toughest enemies in the game. During the fight, vertibirds land and drop off more troops and shoot rockets at you during flyby attacks.

The final area is a satellite tower, where you make the final decision of the main quest and fight off more Enclave enemies as you make your way up the tower. This area is made easier if you reprogrammed the Enclave robots, as they're making an effort to contain them. The Brotherhood is now making bombing runs outside, and you can hear the bombs go off during your combat inside. After you've done what you need to do, you're picked up by a vertibird commandeered by the Brotherhood of Steel.

National Archives
In a semi-accurate reproduction of the actual archives you encounter Sidney, a treasure hunter looking for the Declaration of Independence. Features include a standoff in the Archives' Rotunda where you hold your ground alongside Sidney against waves of incoming super mutants. Sidney also guides you through and an underground service area being guarded by military robots, offering shortcuts if your skills are sufficient.

Farragut West Station
A metro station that is the most probable route into DC on the main quest, the player gets to fill a ghoul-infested area with flammable gas, and learns how to use a laser pistol to ignite the gas.

Downtown
The slave quarters in The Pitt DLC, this area is a filthy working and living environment for the Pitt's slave population. There is an upper area that is blocked off from the player at the start of the DLC, where Pitt Raiders can be seen walking above the player. This enforces the atmosphere that the slaves are lower-class citizens without access to the nicer, raider-inhabited upper areas. While most settlements are handled by world artists, the amount of combat here (raider vs player, raider vs slave, slave vs player) necessitated the involvement of a level designer.

Hangar
In Mothership Zeta, the player get close to the objective in the Hangar before setting off an alarm. The player then gets to fend off numerous waves of enemies by activating repulsion pylons originally used to help alien spacecraft land. The explosions from the pylons send enemy aliens and their helper robots flying. When creating this, I made a flexible scripted system that allowed me to rapidly change the spawn frequency, amount of spawns and difficulty of enemies, and also break the attacks into distinct waves in order to not overwhelm the player.

Weapons Lab
Further on in Mothership Zeta, you encounter the weapons testing facility. In this area, there are numerous testing stations, including a station where you can teleport mutant bovines (Brahmin) from the surface of the earth, who are then blasted to pieces by helper robots carrying experimental, unique weapons. You can destroy these robots and take their unique weapons. You also come across a target practice range that teleports numerous wasteland creatures and raiders into the spaceship for you to shoot. Successful target practice will award you with an alien weaponry perk.

Other Locations:
Galaxy News Radio
This is one of the first points the player travels to if following the main quest.

Meresti Metro Station
A major point on the Blood Ties quest, this area is the home of a reclusive cult.

Oasis
I'm responsible for some of the caves under Oasis, important to the Oasis quest.

Rivet City's Broken Bow
A slanted, half-underwater area that is potentially part of the Replicated Man and Wasteland Survival Guide quests.

Vault 112
A super high-tech area that the player must visit on the main quest.

Bethesda Ruins
A fortified set of buildings overrun by raiders.

Deathclaw Sanctuary
In the mountainous northwest, there is a cave full of deathclaws. Only the toughest or sneakiest will survive long enough to get the great loot that's down there.

Shalebridge
Actually two separate areas, one is inhabited by friendly worker ants and allows the player to perform a freeform activity to acquire ant nectar, a powerful chem. These friendly worker ants are being harassed by a neighboring group of ants. By going down the twisting, vertigo-inducing tunnels of the aggressor ant hive and taking out their queen, you encourage the other ants to make ant nectar more quickly.

County Sewer Mainline
A fun sewer romp takes the player along a twisting series of pipes and processing stations. You might just encounter Gallo, an insane cannibal ghoul hermit who collects useful items and antique Nuka Cola merchandise.

L.O.B. Enterprises
A company under investigation for developing weapons with China, the building was occupied by government military robots when the bombs fell. To this day, the robots still guard the halls of the building, waiting for new instructions.

Anchorage War Memorial
A complex beneath this memorial contains several dead wastelanders, monstrous mirelurks and a makeshift kitchen. It is up to the player to determine what became of the wastelanders, and follow a breadcrumb trail of clues to a hidden stash of loot.

Georgetown
An outdoor region in DC, containing a slew of Super Mutants and various freeform activities.

L'Enfant Plaza
Another outdoor region in DC, connecting various locations together and providing exploratory gameplay.

Franklin Metro Utility
This high-level ghoul-infested area contains some serious combat. The player also gets to explore what was once a ghoul settlement, and is now a hive of insane feral ghouls.

Tenleytown/Friendship Station
On the way to the GNR building on the main quest, it's quite probable that the player will get to go through this scenic, low level dungeon. The player gets to loot dead fallen wastelanders who were attacked by the feral ghouls in the area.

Uptown
The raider-only settlement in The Pitt was also put together by me instead of a world artist due to the high amount of combat involved in this area. There are multiple combinations of combat possible depending on the player's choices, including a scene where the player powers down the lights in the area and Trogs (violent, light-hating subhuman mutants) flood the area killing off all of the raiders. The player gets to finish off any survivors left after the battle.

Abandoned Apartments
Created based on a need for more exploratory content in The Pitt, I created an apartment footprint and duplicated it in order to make a multi-story apartment building. Then, to make the area interesting, I collapsed walls, floor and ceilings to make a non-standard path for the player. This experiment in simplicity took a familiar setting and turned it on its end, causing the player to navigate the building in a unique way.

Haven
The boss of The Pitt lives in this towering skyscraper. It was a challenge to make the building seem huge from the inside while keeping the player focused on the main path of the quest.

Ritual Site
Located in Point Lookout, this part cave, part masonry space looks unique due to the integration of the cave kit and an exterior stone wall kit found in DC. It is the resting place of the Book of the Dead, and a creepy area for the player to explore in Point Lookout's The Dark Heart of Blackhall quest.

Robot Assembly
In Mothership Zeta, the player is accompanied by a tech-savvy scavenger through the robot assembly plant. Highlights include blowing up part of the assembly line in order to get to the next area, and a boss fight involving an alien who has a robot control device. You can watch the alien wake up helper robots from their pods, and they go to attack you. You can loot the control device from this alien, and then activate dormant robots with it throughout the rest of the DLC. These helper robots will follow you around and attack your enemies for you.

Experimentation Lab
This macabre area is where the humans are being experimented on. The player encounters hostile alien/human hybrids as well as gruesome experimentation rooms. Highlights include unleashing a group of these hybrid abominations on alien researchers.