GunNac

GunNac is a Shoot'Em Up by Compile released for the NES in 1991.

The game's plot tells the story of a far-off artificial solar system named IOTA Synthetica, which is being colonized by the people of Earth due to depleted resources. The real trouble begins when a wave of cosmic energy causes animals and even inanimate objects to come alive and start attacking the people. All is not lost, for the Space Federation has enlisted the help of Gun Nac! Gun Nac's mission is to search to system's 7 planets for signs of hostile forces, perhaps even an invader...

While GunNac is fairly obscure, it is rather popular for its smooth gameplay, detailed graphics, and quirky setting. It also has an unusually high degree of customization.

Tropes used in GunNac include:

1-Up: Not only provides an extra life, but it also doubles as a Wing attachment. Depending on whether or not the ship has a Wing attached, each 1-up token collected potentially allows Gun Nac to take up to two extra hits per game.
Attack of the 50-Foot Whatever: And there are plenty of 50-foot whatevers to go around.
Beam Spam: The Type-5 Weapon, especially when fully upgraded.
- This also applies to the flamethrower (Type-4) weapon. Despite the beams becoming shorter the longer the fire button is held, repeated tapping the fire means not having to worry about it losing its range.
Bonus Stage: Area 0, accessible only from the level select.
Collision Damage
Easier Than Easy: Novice difficulty + Non-Death = Why bother playing?
Easy Mode Mockery: If you beat the game on Novice difficulty, you won't see the full ending. This is also true if you have Non-Death activated, no matter the difficulty.
Every 10,000 Points: You receive a 1-Up at certain score plateaus.
Everything Is Trying to Kill You: Quite literally. Everything ranging from bunnies, lighters, toilet paper, umbrellas, coins, pottery... and so forth.
Fire, Ice, Lightning: The sub-weapon bombs come in 4 flavors: Blizzard, Fire, Thunder and Water.
Getting Crap Past the Radar: The Stage 3 mid-boss is a humanoid mermaid. In order to defeat her, you have to blow off both of her arms.
God Mode: Non-Death.
Homing Projectile: Weapon type 3 in Gun Nac's arsenal, as well as some of the enemies' attacks.
Kill It with Fire: Weapon type 4.
- Many of the enemy craft in Area 2 use fire-based attacks.
Made of Explodium: Everything.
Making a Splash: The Type-W bomb fills the entire screen with a cascade of droplets, arguably making it the most effective of the 4 bombs.
Maneki Neko: The mid-boss in Area 5.
Mercy Invincibility: You die in one hit, so thankfully every item you pick up makes you invulnerable for a split second.
Miko: The girl in the extended intro and ending scenes.
- It is implied that the shrine maiden is Gun Nac.
Moon Rabbit: Area 1 is nothing but this trope.
Multiple Endings
Nick Arcade: Notable because it appeared on some episodes with the so-called "Nick Arcade Beta" version of Sonic 2.
Nintendo Hard: Expert difficulty + Ricochet of Bullets + Speed Has Priority = Aggrivation.
One-Hit-Point Wonder: Partially averted. Picking up a Wing upgrade not only allows more powerful guns to be used, it also allows Gun Nac to absorb one hit without exploding. However, without a Wing attachment equipped, it's one hit, you're dead.
Playing with Fire: Type-4 weapon is a massive flamethrower. Possibly the most useful of the 5 types, especially when coupled with the Wing upgrade.
Video Game Cheats: Holding down both the A and B buttons during the intro story will give you the option to activate Non-Death.
When Trees Attack: Area 4 lives and breathes this theme.
Widget Series: From the moon/rabbit symbolism to fighting a lucky cat figurine in Area 5, I'd say this game fits the criteria well.