Well, since I came up with a couple more level ideas, I decided to post a list of my current/planned levels with a few short descriptions.
Episode 1: A New InvasionThe Flemoids have invaded! Get to the IFC Army Reserve base pronto!
E1M1: ChexburgThe beginning... where all quests start.
E1M2: Chexaco World HQThe world headquarters of one of the biggest fuel suppliers on Ralston!
E1M3: Cheerio AvenueWhat mod would be complete without some city streets?
E1M4: Eatmore MansionA sprawling mansion outside Chexburg.
E1M5: Chexview MallThe biggest mall this side of Chex City, with Rice Aid, The Bon Bon, and SpecialKmart all under one roof!
E1M6: Chexville HotelRest and relaxation after a long trip... oh wait, there's a Flemoid in the pool.
E1M7: Chexville GreenhouseGrowing plants all year round in state of the art greenhouses.
E1M8: Chexville City LimitsYou're almost to the IFC Army Reserve base! Go for it!
E1M9: Undeveloped (secret)
No, your eyes aren't going crazy, this area is truly undeveloped!
Episode 2: First LightYou've been separated from your squadron. Get to the meeting place fast!
E2M1: Sunrise PlazaA great place to do some early morning shopping... aw drat, you crashed your ship.
E2M2: Chexonite Mineral MineOne of Ralston's biggest mines, with a top-notch flood control system.
E2M3: Chexworth State ParkA park to enjoy the beautiful Chexworth gorge. Comes with a free maze.
E2M4: Charles Kix DamThe Charles Kix Dam, situated in Chexworth gorge, supplies power to Chexburg and many other towns around Chex City.
E2M5: DownriverYou made it out of the dam safely! Now for a leisurely hike down the gorge.
E2M6: Uncharted CaveAw snap, you fell into a cave nobody's been in before... and your map's not working... great.
E2M7: Historic RuinsThe old seaside ruins nobody goes to anymore... Enjoy the view!
E2M8: Mills Zorch FactoryWhat better place for a boss fight? Plenty of ammo, traps, danger....
E2M9: In My Day (secret)
Old school FPS... CQ style!
Episode 3: The Great WarThe great war against the Flemoid invasion is on!
E3M1: IFC Zorcher ArsenalGet your zorcher and get to the battlefront!
E3M2: Bottomland BunkerYou've retreated to the bunkers to wait out the onslaught for a little while.
E3M3: Stillwater Sewage Co.Ah, a brilliant idea! Go through the sewer on a special mission to infiltrate the Flemoid forces!
E3M4: The UndertunnelsThe Undertunnels. What more could be said?
E3M5: Behind Enemy LinesYou made it behind enemy lines! Go get 'im!
E3M6: This level has not been come up with yet.
E3M7: Beachside ResortA lovely beachside resort, complete with slime vendors to quench your life thirst.
E3M8: Carnation CastleThe majestic castle... a perfect place for the Flemoid leader...
E3M9: Wheaties Arena (secret)
Prove your skills as a fighter on this tricky arena course! Be a champion!
Episode 4: The Final QuestThey've tracked the source of the invasion to a portal on Ralston's moon! Get up there now!
E4M1: Mission ControlGreat, everybody at Mission Control's been slimed... I guess you'll have to launch on your own.
E4M2: Corn CanaveralGet up the tower and into the rocket!
E4M3: Outpost S.24The main outpost on Ralston's moon. Home of everything techno.
E4M4: Abandonded MineAn old mine that hasn't been used for years. Be careful.
E4M5: Slime RiverLooks like the Flemoid portal is oozing slime, creating a big river...
E4M6: Flemoid Research CenterA massive IFC compound, housing some of the best laboratories and test equipment in the solar system.
E4M7: This level has not been come up with yet.
E4M8: The Last BattleThe last battle. Speaks for itself.
E4M9: (secret)
This level has not been come up with yet.
Levels E1M1-9 are complete and released, E2M1-3 are in progress.