WebKit

card-xp_2

card-PrhP

Doubles the player character's speed. For playability reasons, you have to enable this when starting gameplay. Under Quintupler, multiplies speed by six instead, which you must also enable manually.

Speed Up

Grants an extra jump or mini-dash. Also allows you to use the grounded dash before or after a jump. Under Quintupler, gives five extra jumps instead, for a total of seven.

Triple Jump

Gives 500 additional points when starting this deck. Under the effect of Quintupler, gives 2500 points instead.

Headstart Pass

Doubles time given when Panic Time starts. Under the effect of Quintupler, multiplies it by six instead. 

Easier Panic Time

You can dash into these guys (pictured on pass) to KO them. If you have the Effect Quintupler, These Guys will give 5 Chain and will die on contact with Titanium (the player character).

Dash Into These Guys To KO Them

Multiplies all effects off all other passes on this deck that you own. Will have no effect on passes you don't own.

Effect Quintupler

health

gamemode

timer

keypieces

song

chaintime

score

panic

s-rank-req

card-hksx

card-SRBf

card-pQqs

card-Zs0I

COUNTDOWN

kitchen

card-HPZi

card-qlwg

card-stnp

Twenty-one math lessons. An Osc, Bfdi, Christmas game by @SurgeAlloy, playable free in your browser on Castle.

BFDI: Twenty-one math lessons - Play Free Online | Castle

Twenty-one math lessons. - by @SurgeAlloy on Castle

BFDI: Twenty-one math lessons

More #christmas2025 games