if we're going to go into the mininuke we should add other downloadable tropes
Gun research: The sheer amount of weaponry on the Blockland Forums would probably blow one's mind. Tier+Tactical doesn't help.
Bottomless Magazines: The classic Blockland arsenal (and weapons based around it) have no need to reload, and even no ammo system. Certain mods get around this, like Rotondo's Zombie Mod.
Everything is a Pinto: Shoot anything. Do it. Chances are, it'll explode. Even if it's a player. Some mods take this even further, with them exploding into gibs.
Good Guns, Bad Guns: The Classic Battle Rifle is clearly an AK-47, despite the name: It's counterpart, the Classic Assault Rifle, is an M-16.
Short Ranged Long Ranged Weapon: "Sniper Duels" generally consist of fights at point-blank with said high powered rifles.
Handcannon: Every other weapon is wielded in one hand. Several are magnums that fire rounds larger then the players head.
Acceptable Breaks from Reality: Physics has completely flown the coop... at least, until you shoot something.
Standard FPS Guns: It's become a trend as of recently.
Downloadable Content: The game's a powerful building tool on it's own, but much of the content comes from the add-ons forum.
Crowning Moment of Funny: A bit meta, but much of the 'complaints' the game gets are from the parents of kids (generally far too young to be online) telling the creator of the game to make the internet more kid-safe. He posts these conversations on the forums, as a mailbag.
Accidental Aiming Skills: Due to the 'traveling' nature of weaponry, many times a player won't so much shoot their target as their target walks into their bullet. Distinctly different then leading your shots.
Bullet Dodges You: Tier+Tactical's RPG has the uncanny ability to fly AWAY from your target. Experienced players learn to just aim at the ground.
etc, etc