Ever wonder who's a better gamer? you or your friends? the debate is over, on Kongregate you gain levels, the more games you play the more achievements you earn gain you levels. The Kongregate website itself is basically a game, you earn achievements, do quests, and gain levels, then you can also earn Kongai Cards basically Kongregate has a card game simalir to magic the gathering or yu-gi-oh only alot simpler. Kongregate allows you to earn the cards or buy them, to earn the cards you must complete a challenge, the challenges are special game achievements.
Kongregate also supports Developers quite a bit, they have a tip jar for each game where players can donate money to the creators of the games, they have developer forums, developer api, and other fun stuff!
Addicting as hell Kongregate is my favorite Flash Arcade!
Try Out Kongregate!
Newgrounds is truly an entertainment world. For a long time internet memes were popping out of here like crazy, that's slowed down now but the site is still kick ass.
The quality and amount of games is immense.
CrazyMonkey is an awesome game site all the games are high quality and pretty addicting. This site is fully dedicated to games.
I have to say I keep coming back here to play Adrenaline Challenge and a few other addicting games.
Miniclip offers tons of games, has tons of classics. But not a very good community setup in my opinion.
However Miniclip has one nice feature they have a thing called Sketch Star which basically lets you make your own flash animation without any flash knowledge.
I don't like Miniclip a whole lot to be honest.
I'm sorry there are others I haven't added to my review but I don't have time to go through every site on the planet.
Out of all of these Flash Arcades Kongregate is the best in my opinion and Newgrounds is right up there too!