Bonesaw

Bonesaw: The Game is a freeware game by Kyle Pulver.

The game chronicles the events right before a hockey game at Clarkson University as the player attempts to rescue his teammates from an evil referee who has banished them to an "interdimentional penalty box."

The gameplay is best described as a Beat'Em Up crossed with a Platform Game.

Not to be confused with the character BONESAW.

Tropes used in Bonesaw include:

100% Completion: Required to get the good ending, let alone encounter the bonus boss.
Boss Rush
Bonus Boss: The first one's a Palette Swap of the player character. The other bonus boss is a professor of Clarkson University.
Bottomless Pits: Plenty of them. Your character can survive falls from ridiculous heights otherwise. The final boss fight even has you fight the boss as you fall from orbit before landing in the Clarkson University hockey rink.
Collision Damage: Subverted, but if you get close to the large bosses when they aren't vulnerable, they will launch an attack that looks like collision damage.
Late to the Party: This is why the Player Character wasn't kidnapped at the beginning. You were out getting pulled pork sandwiches.
Leitmotif: There is a recurring riff that shows up in the title theme, the lava world music, the music for the first form of the final boss, and most awesomely, the challenge stage music. This was intentional by the composer, who added this riff in multiple songs to reinforce the idea of the songs being part of a collection.
Nintendo Hard: The later stages are very unforgiving.
Punch Clock Villain: The penguin, who just says he's the boss of these parts rather than being angry, and later helps you. When rematching the dragon, he also apologizes for being angry the first time.
Super Mode: The Bonesaw.
Tactical Suicide Boss: Five of the bosses use an attack or move that makes them vulnerable to basic attacks.
Tennis Boss: Some regular bosses in the game can have their attack reflected back at them, but only the first Bonus Boss will do a tennis match.