Cygnus the Cutie is a game in which you eat stars to grow, but try to avoid asteroids because you will become a black hole.
The game is complete and fully playable, and features original graphics and design.

Cygnus the Cutie (instant-play version)
Cygnus the Cutie (with source)

IPSS is a two-player game in which each player tries to destroy the other. The players can jump between planets and move them.
The game is complete and fully playable, and feature original art and design.

Intergalactic Planetary Super Showdown

Nyx is a unique game in which you use lightning to zap creeps across the screen, in order to turn the day into night.
The game is complete and fully playable, and features original graphics, sound, and design.

Nyx (instant-play version)
Nyx (with source)
Facebook page (with screenshots)

Gravity Flyer is an interesting game in which you shoot evil geometric shapes with matching color space debris!
The game is complete and fully playable, and features original graphics, sound, and design.

Gravity Flyer (Windows installer)

Grid[z] is a two-player game in which players try to place as many of their pieces on the board before running out of moves. Players gain and lose points for winning and losing games, and are ranked globally by these points.
The game features good integration with Facebook and original graphics. It is published and fully playable, but still has minor bugs and is being developed.

Grid[z]
Facebook page

In this game, creeps can fly over towers, but not over trees, which the user can reposition. The creeps get smart this time, going out of the way to avoid towers.
The game features several levels, creeps, towers, difficulty levels, and sound effects. The game is complete and fully playable.
Graphics, sound effects, and music were provided by third parties (see the readme file).

Operation Flytrap (instant-play version)
Operation Flytrap (with source)
Facebook page (with screenshots)
Author’s blog post (with a thorough description of the game)

In this game, creeps follow through a pre-set maze from the top of the screen to the bottom. The player places towers which autonomously shoot toward the center line of the maze. The major twist is that your funds also serve as your life.
The game features multiple types of enemies, waves, towers, and maps, as well as music. The game is complete and fully playable.
Graphics and fonts of the SDL version are provided under the GPLv2 and the music is public domain.

Tower of Mediocrity
Tower of Mediocrity (tarball / source only)
Website

This is a simple, keyboard-controlled game of missile avoidance; there are no bonuses.
Despite the fact that the player’s ship is a solid green rectangle, this game has decent gameplay and requires quick button pressing. There are a few types of enemies, including a boss, who fires multiple missile patterns. The game plays increasingly hard levels until the player has died. The game is complete and fully playable.
Sound effects and music were provided by third parties (see the readme file).

The Shmup of Death (instant-play version)
The Shmup of Death (with source)
Author’s blog post (with a thorough description of the game)

Paint Flinger is a two player game in which each player must try and fling sheep, cows, and ducks onto the other player’s sides, in which the animals will proceed to paint the ground when they collide with it . The player to fling the most animals onto the other player’s side wins! Extra points are awarded the further an animal is flung. But be warned, trucks and cars sometimes come down the road which makes it difficult to fling animals to the other side!

Paint Flinger (instant-play version)

Ultimate Online Checkers is based on the popular board game, but it adds power-ups, such as the ability to purchase a king early in the game.
This polished game features online multiplayer gameplay and original artwork. It is complete and fully playable.

Ultimate Online Checkers (instant-play version)
Author’s description of the game