YMMV / BPM: Bullets Per Minute

• Awesome Music: Being a rhythm game this is to be expected and what the game is built on, but when was the last time gunshots and reload sounds meshed so well with a game's OST?
• Anti-Climax Boss: Nidhogg can be this: if you've managed to make it to the Final Boss, you probably have good stats and a combination of weapons, abilities and items that let you cut through enemies with ease. Nidhogg has powerful attacks and likes to fly around, but he's nothing special otherwise, and he can die very quickly if you have a particularly good set up.
• Demonic Spiders: Guardians are shielded from the front and fire rapid shots that require dashing to avoid.
• Difficulty Spike: Playing the game on Easy is no picnic, mind you, but the jump to Hard is quite a surprise: enemy spawns are completely shifted around, so that monsters you didn't run into until Svartelfheim on Easy can show up in Asgard on Hard, long before you have the weapons and stats to easily deal with them. The game otherwise avoids being Numerical Hard, as damage remains consistent.
• Game-Breaker:
  • The Best Defense shield gives you infinite ammo which means that weapons that have a longer reload times like the Revolver or the Pump Shotgun can now be fired with impunity, making them vastly more powerful than they already were.
  • To a lesser extent Clip Ups do the same by boosting the DPS of weapons whose high damage is balanced by their low clip size.
  • Seiðr's Blessing are leggings that will slowly drain enemy health, meaning you could focus more on dodging and the room will eventually get cleared. This also trivializes boss fights, because the health drain is not insignificant.
  • Any form of regenerating health or shield significantly increases the player's survivability as well as allowing them to take Sword of Damocles items for free and earn extra money from challenge rooms at far less risk.
  • If Asgard Crypts spawn, the Tribute altar found there is reusable up to 50 times and gives a random stat up (or Clip Up if a stat is maxed out) per coin offered for a very early power spike that can hold the rest of the run together.
  • The Adventurer's Fedora lets you choose which gear slot an item goes in, meaning the player can equip multiple game breaker items that would normally be mutually exclusive (e.g. a double damage shield with an armour-generating shield). It effectively enables a player to equip the four most useful items they find on a run, regardless of class.
  • The Prestige room; for 30 coins, you can make permanent all items you have currently equipped, and get up to four more. Being able to have the effects of eight items considerably ups the chances of victory.
• Goddamned Bats: In this case it's the literal bats that make up the forces of Helheim. They're weak and easy to kill but often come in packs.
• Most Wonderful Sound: While you're required to do everything on beat, there's something extremely satisfying the soft reload clicks that a gun makes in time with the music. There's also the guitar riff you get when you drop a boss's health to zero and the victory fanfare after you finish them off for good.