Resident Evil Gaiden

The sixth game in the Resident Evil series, released for the Game Boy Color. Unlike the rest of the series it was developed by M4 Limited rather than Capcom.

After the events of Resident Evil 1 and 2, Barry Burton and Leon Kennedy joined a secret anti-Umbrella organisation, compromised of former S.T.A.R.S. members and ex-Umbrella employees and set on putting a stop to the operations of the evil medical corporation.

The game starts with the escape of a shape-shifting Bio-Organic Weapon developed at Umbrella Labs. Leon managed to track it as far as the ocean cruiser The Starlight before contact with him was lost. Now Barry must board the ship to find him, as well as figure out the mystery of a young girl he finds aboard.

The gameplay mechanics are similar to that of the Resident Evil Gun Survivor series, with the game being in third person while changing to first person for shooting zombies. Also similar to the Survivor series is that it's widely considered to be one of the lesser points in the series, and is often regarded as non-canon by fans and the creators alike. On the other hand its puzzles and story have been praised by some critics.

Tropes used in Resident Evil Gaiden include:

A Day in the Limelight: For Barry, one of the side characters from the original Resident Evil.
Adaptation Dye Job: In this game Barry is a redhead, while in the rest of the series he's a brunet.
Alien Blood: The escaped B.O.W. has green blood, as does the parasite B.O.W. in Lucia. The last shot of the game has a close up of "Leon" with a small cut oozing green blood on his neck.
All of the Other Reindeer: Lucia was bullied in school due to her weird powers.
Bag of Holding: Unlike most other games in the series, this one gives you an unlimited inventory.
Bittersweet Ending: Barry finds Leon and both of them survive with Lucia. Except for the fact that Leon might actually be the parasite B.O.W.
Boom! Headshot!: What happens if you manage to hit the small dark purple area in combat mode.
Boring but Practical: The higher a weapon's power, the less accurate it is, so the pistol tends to be pretty effective even a bit later in the games.
Boss in Mook Clothing: One of the Palette Swap zombies later in the game are powerful enough to knock off more than a third of your health with just one hit.
Canon Discontinuity: The events of this game seem to be pretty much ignored by the creators. Leon at the end of the game being the parasite B.O.W. in disguise is never brought up again and rewritten out of the series.
Combat Tentacles: Subverted. The escaped B.O.W. spouts tentacles from its chest and uses them to grab Lucia in a cutscene, but when fighting he just uses his fists.
Continuity Nod:
- This isn't the first time Barry has been a mole for Umbrella while still remaining fairly innocent.
- It's also not the first time Leon's had to temporarily look after a little girl infected by a parasite and later cured.
Cruel Twist Ending: Implying that "Leon" may actually be the parasite B.O.W.
Deadly Gas: The gas gun is potent enough to kill all zombies in the room, though the drawback is that it has very little ammo.
Damsel in Distress: Lucia. She gets attacked and kidnapped by the escaped B.O.W., held at gunpoint by Barry after Umbrella try and take her, and then gets dragged into the sea by the parasite B.O.W.
Fake Defector: Barry pretends to turn on Leon and Lucia so he can infiltrator Umbrella.
First/Third-Person Shooter: A hybrid much like the Resident Evil Gun Survivor series. You navigate in third person but enter first person mode when fighting enemies.
Gaiden Game: It's even in the title.
Ghost Ship: Everyone on The Starlight sans the main characters have been completely zombified.
Guide Dang It: The game doesn't prompt you to use any key items, so you might end up having to walk up to every door that could conceivably fit with a certain item and try it until you get the right one.
Healing Herbs: A staple of the series, but in this game they come already mashed up and in green, yellow and red (light, medium and large healing respectively) as well as blue and purple for poison.
Hostage Situation: Barry holds Lucia at gunpoint so that they can escape the Umbrella submarine. Different from some examples in that it's the protagonist taking another good guy hostage.
I Just Want to Be Normal: Lucia, due to her being picked on for her weird powers.
Kill and Replace: At the end of the game it's implied that the parasite B.O.W. managed to successfully do this with Leon.
Mission Control: The HQ will occasionally call in to spout some exposition.
Mysterious Waif: Lucia.
No Body Left Behind: The escaped B.O.W. does this when it's first defeated.
Non-Lethal KO: Occasionally after defeating a zombie they'll fall to the ground, but if you pass them again they'll still be alive and jump you, forcing you into combat again.
Recurring Boss: The escaped B.O.W. shows up four times, and the parasite B.O.W. is fought thrice.
Send in the Search Team: Partly the reason why Barry goes to The Starlight is to find Leon, who's lost contact with HQ. Turns out he fell down a hole in the ship and was knocked out for 24 hours.
Spot the Imposter: The parasite B.O.W. impersonates Lucia during the game. It's found out when Lucia cuts her hand and shows her normal coloured blood.
Stock Super Powers: Lucia has a Healing Factor and super hearing, which makes Barry suspect that she might be the escaped B.O.W. He's half right. It's actually due to the different parasite B.O.W. she's infected with, and she loses her powers when it's extracted.
Tempting Fate: Leon to a group of Umbrella soldiers:

Leon: What are you going to do...shoot me?
Guards: OPEN FIRE! (start shooting)
Leon: I can't believe they opened fire!

Voluntary Shapeshifting: The escaped and parasite B.O.W.'s are able to shapeshift into human beings. Unluckily for them Lucia is able to see right through the deception.
Where the Hell Is Springfield?: Like the rest of the series. The game simply states that the anti-Umbrella group's base is somewhere in North America, while the boat's location is somewhere in the Atlantic.