While hockey is still the same game, there are a few rule changes when you go from the NHL to the Olympics/IIHF.   Read up on some of the differences between the two:

NHL

Olympics
Ice Size 200′ x 85′ 200′ x 98′
Goal Distance from Boards 11′ 13′
Icing Hybrid – Linesman judgement based on leading skater No Touch – Whistle blows when puck crosses goal line
Overtime 4-on-4 for five minutes 4-on-4 for five minutes.
In playoff game, 4-on-4 for ten minutes.
In gold medal game, 4-on-4 for twenty minutes.
Faceoffs Visiting player’s stick down first Attacking player’s stick down first
Rosters 18 skaters, two goalies 20 skaters, two goalies
Trapezoid Goaltender may only play puck above goal line or within trapezoid No restriction on where goaltender plays puck.
Goalie Equipment Size restrictions based on size of goaltender No restriction on size of equipment
Helmets Players permitted to play without helmet if knocked off during play. Must be replaced at next stoppage. Players must return to bench immediately if helmet lost during play.
Head Shots Anywhere from minor penalty to major/game misconduct. Minor penalty includes mandatory 10-minute misconduct. Major penalty includes a game misconduct.
Fighting Five-minute major penalty Five-minute major penalty plus match penalty; player is tossed from the game.
Penalty Shots Fouled player must take the shot Any player on the team eligible to take the shot
Goalie Crease Players may be allowed in the crease provided they do not interfere with goaltender’s ability to make a save. Play will be stopped if attacking player is in the creaase. Faceoff will come outside the zone.

 

Additionally, women’s Olympic hockey is a no-checking sport, so watch for the occasional penalty for a Body Check.