Clash at Demonhead

Clash at Demonhead (called Dengeki Big Bang! in Japan) is an open-ended action adventure game for the Nintendo Entertainment System.

You take on the role of a soldier named Billy "Big Bang" Blitz, who is contacted during a vacation with his girlfriend Mary about a kidnapping attempt on Professor Plum, a scientist who constructed a Doomsday Bomb that will destroy the world. At the start of his mission, Bang encounters Tom Guycot, the kidnapper. Guycot tells him that he and the seven governors of Demonhead Mountain have taken the medallions used to power the device, and issues a challenge to Bang to try and find them. With no choice but to cut his vacation short, Bang goes off to find the professor and prevent the world from being destroyed...

Not to be confused with the band from Scott Pilgrim. But it's obviously named after the game, which Bryan Lee O'Malley claims was the first NES game he ever had.

Tropes used in this game:

 * Betting Minigame
 * Bodyguard Babes: Mush, boss of Route 16, has a pair.
 * Deflector Shield: The Barrier item creates a force field around Bang that blocks enemy bullets.
 * Destructible Projectiles
 * Doomsday Device
 * Everything's Even Worse With Sharks: The appropriately-named Shark, who lords over Route 22. The battle takes place underwater, so you'll need an Aqua Lung to survive.
 * Fairy Companion: Faysha.
 * Giant Space Flea From Nowhere: The Demon itself has nothing to do with Guycott or the Doomsday Device. Interestingly, it shows up at the middle of the game, and nobody, good or bad, saw that coming.
 * Guide Dang It: There's no way to know where to find Shark..to find him, you have to.
 * Hopeless Boss Fight: The Demon.
 * Jet Pack
 * Lava Is Boiling Kool-Aid: A Supersuit is mandatory to even go anywhere near it.
 * Luck-Based Mission:
 * Meaningful Name: Guycot is a pun for the Japanese word for "skull".
 * Name's the Same: "Professor Plum" has nothing to do with the board game Clue.
 * Nintendo Hard
 * Non Lethal Bottomless Pits: Subverted. While falling into pits doesn't kill you, you get taken to an area where you have to fight your way back to the surface, making you start the route over again.
 * Oxygen Meter: The timer for the Aqualung acts as one. Once it runs out, you lose one point of health for every second you're underwater.
 * Painfully-Slow Projectile
 * Password Slot Machine:
 * Plot Coupon: The medallions.
 * Power Floats: Acquiring the "Levitation" power-up allows Bang to float around in the air for a short time.
 * Sizeshifter: Max, the Governor of Route 7, starts out as a tiny runt of a boss, but as you damage him, he increases in size until he's big enough to float around and start firing smaller versions of himself at you.
 * Skippable Boss:.
 * Spread Shot: The Big Shot/Thundershot weapon fires a powerful spread of projectiles, but has limited ammunition.
 * Sprint Shoes: The Power Boots boost your running speed for a short time.
 * Sword of Plot Advancement: The Sword of Apollo.
 * Villains Never Lie: Subverted. Guycot lied about
 * Warmup Boss: Gazh, the boss of Route 11, is usually the first one players fight, and he has a very predictable fight pattern (dash back and forth, get shot, shoot a line of fireballs, rinse, repeat).
 * Weaponized Headgear: Mush like to toss his mushroom-shaped cap at you.
 * We Sell Everything
 * Weaponized Headgear: Mush like to toss his mushroom-shaped cap at you.
 * We Sell Everything