Bloons Tower Defense 4
[http://www.playedonline.com/game/597276/bloons-tower-defense-4.html]

Canabalt
[http://www.playedonline.com/game/597512/canabalt.html]

Toss the Turtle
[http://www.playedonline.com/game/596997/toss-the-turtle.html]

Upgrade Complete
[http://www.playedonline.com/game/61764/upgrade-complete.html]

Mastermind World Conqueror
[http://www.playedonline.com/game/597098/mastermind-world-conquerer.html]

Pandemic
[http://www.playedonline.com/game/597567/pandemic.html]

Hedgehog launch
[http://www.playedonline.com/game/58656/Hedgehog-Launch.html]

Fancy Pants 2
[http://www.playedonline.com/game/597071/fancy-pants-adventure-world-2.html]

Portal the flash version
[http://www.playedonline.com/game/58659/Portal-The-Flash-Version.html]

Age of war
[http://www.playedonline.com/game/58697/Age-of-War.html]

The last stand
[http://www.playedonline.com/game/58832/The-Last-Stand.html]

Sonny
[http://www.playedonline.com/game/58658/Sonny.html]

Murloc RPG
[http://www.playedonline.com/game/597480/murloc-rpg.html]

Red
[http://www.playedonline.com/game/597566/-red-.html]

Fancy Pants
[http://www.playedonline.com/game/597478/the-fancy-pants-adventures.html]

BowMaster Prelude
[http://www.playedonline.com/game/58835/BowMaster-Prelude.html]

Stick fighter
[http://www.playedonline.com/game/597476/stick-fighter.html]

Zelda
[http://www.playedonline.com/game/597477/zelda-seeds-of-darkness.html]

Demonic Defense 4
[http://www.playedonline.com/game/218/Demonic-Defence-4.html]

Dad N me
[http://www.playedonline.com/game/58691/Dad-N_-Me.html]




source: http://www.playedonline.com/blog/2010/01/21/the-best-flash-games-of-the-past-decade