Ice Blocks

Ice Blocks
Margin time	96
Target points	120
Offsetting	Continuous
All clear bonus	Preset 4-chain

Ice Blocks (こおりづけ, Koorizuke) is a ruleset featured in Puyo Puyo! 15th Anniversary, Puyo Puyo!! 20th Anniversary, Puyo Puyo Chronicle, and Puyo Puyo Puzzle Pop. In Puyo Puyo Puzzle Pop, the mode is called Frozen.

Gameplay

Ice Block rules uses a combination of Tsu rule (only pairs, 96-second margin time) and Fever rule (Continuous offset, 4-chain All Clear bonus) traits. However, what separates Ice Block rule from other gameplay rules are the eponymous Ice Blocks. Instead of sending standard Garbage Puyos, players send frozen-over color Puyos to their opponents. The ice fractures over the course of three "turns," after which the Puyos can be used as normal. An ice block will immediately break if it is adjacent to a cleared set of Puyos.

Ice Blocks drop using a preset, character-specific color pattern. These 5x6 patterns can be viewed on the character select screen.

In Puyo Puyo!! 20th Anniversary, the mode is mostly the same, the only differences in this version is the addition of an optional quick drop and filling up the 4th column will no longer cause the player to lose.

Order of Operations

The player places their currently controlled pair.
The game checks for chains.
Any ice blocks in the player's field are fractured.
The game checks for chains.
Ice blocks waiting in the garbage tray are dropped if a chain was not made in step 2 or 4.
The player is disqualified if their third-from-left column is filled.
Return to step 1.

In short, the game does not check to see if a player has lost until after their ice has been fractured. This often leads to instances where a player's field is clogged but a lower set of ice completely shatters, starting a chain that brings the player's Puyo out of the elimination zone.

Difficulty levels (needs verification)

Very Easy: Slowest automatic drop speed.
Easy: Slower automatic drop speed.
Normal: Standard automatic drop speed.
Hard: Faster automatic drop speed.
Very Hard: Fastest automatic drop speed.