PopCap Games produced a lot of classic small PC game works with high playablity, Cosmic Bugs is one of them (developed by Retro64 in 2004). This delicate small puzzle game challenges player's judgment and reaction speed. You may played similar games on the FC console long ago, yet I can't call out all of their names, but two of which should be JezzBall and Qix.

Tasty Blue is a relaxed and funny action-puzzle small indie game developed by Dingo Games from Canada. The goal of game is to climb to the top from the bottom of food chain in the shortest possible time. And the only approach is to eat everything you can eat, whether it is swimming in the sea, walking on the land, or flying in the sky.

Perfect Balance is series of extremely challenging and difficult physics and gravity based small balance game, with ingenious design. Your goal is to, in specific environments, through placing bricks in various shapes to achieve their overall balance.

Atomic Puzzle is a series of small puzzle (eliminating type) games based on mathematical logic operations, created by Kongregate. In game your goal is to eliminate all the balls on the screen - none should be left, otherwise you have to start again.

The World's Hardest Game (short for TWHG) is a series of online flash puzzle games developed by Addicting Games. Be worthy of the name, this game has very simple rules + super high difficulty and playability, and has countless various players in the world.