Gish

This used to be the one linux game that was a relative commercial success. Local multiplayer was a huge hit. Like an early version of Gang Beasts

It's the Gishiest game of all time. I highly recommend it (but go into the betas to enable achievements)

Gish is not just a piece of tar, as its creators claim. It is more like a bouncy ball that has unexpectedly gained softness, a mouth, and a pair of yellow eyes. Gish travels through dungeons, defeats monsters, and solves puzzles to save his beloved. Outside of his adventures, he resembles an illustration from a physics textbook due to his realistic model of object interaction. Newton's laws are embodied in every detail here: from swinging platforms to crossing water obstacles. Even jumps require considering Gish's shape and the surface beneath him, turning each action into an engaging experiment.

Gish stands out because physics is not just a gimmick here, but the core of the gameplay. Every action is tied to the laws of physics. Traps on levels are like small kinematic experiments, and fighting enemies requires using physics to succeed. Jumps, acceleration, and changing mass all require careful attention and calculations.

The game amazes with a variety of obstacles and tasks throughout. Gish gives players the freedom to choose how to solve problems, making the gameplay unique for everyone. This is the embodiment of the "emergent gameplay" idea, where the player creates their own experience and finds unique ways to overcome challenges.

The only drawback of the game is the music. Despite its high quality, the repetition of the same track for extended periods can become tiresome.

The graphics in Gish, although three-dimensional, are displayed in a flat format, creating a clear picture with dynamic lighting and shadows. The game lacks trendy shader effects, but that doesn't prevent it from being engaging. Multiplayer adds even more fun, offering modes like Drag Race and Sumo, which will make you laugh and compete with friends.

Gish is filled with humor and parodies that add charm to the game. The developers at Chronic Logic deserve praise for creating such an original and entertaining game in a short time, demonstrating that they approach their work as art, not just production.

As plenty other reviewers have mentioned, do yourself a favor and play the 1.7.0 version of Gish.
I believe Edmund genuinely wanted to do a good job, but the Anniversary Update feels more like a downgrade than anything? The physics are too fast, you are locked to Easy difficulty, and the ghost on Isle of the Dead just plain doesn't work, turning a thrilling chase sequence into a slightly dangerous walk through the neighbourhood to say hi to Satan. Unfortunately the only upgrade the game got were improved illustrations, which are always nice, but don't really fix the rest of the problems in the update.
Going back to 1.7.0 version, however, I had a blast with Gish. Initially I thought I was going to hate it, and it's kinda hard not to, considering that Gish himself not only controls strange due to his physics based gameplay, but he dies if he does so much as land wrong; but as I kept trying to go for achievements and clearing the levels I was beginning to enjoy myself a lot with his movement.
It's really no surprise Edmund loves the little ball of tar so much, this is genuinely a fun game, with a level editor, a versus mode and even an appearance on Isaac Rebirth, and it's a shame that the Anniversary Update doesn't showcase those highlights well. Maybe Ed will feel the itch to come back and update it someday, who knows.
48 secrets / 10, bring back Hera for the lulz

game looks fun, but you have to use awful arrow keys so im sad, broken fingers

An interesting platformer game where the physics feel weird at first, but after getting used to them, it makes you feel like a speedrunner. It was really satisfying to play, and I would recommend this game even though some levels in world 5 were a bit annoying.

A good game, but at points, frustratingly difficult. The levels themselves shouldn't be too difficult, but the controls and bugs make it an absolute pain. Its clearly very amateur but it still oozes with Edmund McMillen's charm. Now, for the state its in, the 15th anniversary update has added widescreen support and fixed a lot of bugs, it also removed the mode selection, end of level screen, broke achievements, etc. You're able to select the 1,7 (aka the non 15th anniversary update) version from the betas part of properties.