The game has several serious issues that need to be talked about.
The worst is that they launched the game with some critical networking bugs (do a search for dota 2 disconnecting internet); for alot of people (not all but juding by the large number of posts quite a few) the game works fine until they pick their hero and try to play the actual game. They are suddenly locked down with what appears to be a massive lag spike, you cant move or do anything, now n then it'll stutter out a line of chat and eventually take you back to the main screen. If you alt tab out at that point you will find your browser wont work nor anything else net related. I would reset my connection and try again exactly same problem just like so many others. This will only happen when dota 2 tries to put you in a match; BUT here is the worst part...the disconnects are being counted as 'leaving game' and Steam is banning people from normal gameplay for nothing more than their own networking failures.
The other big problem I saw was the champions, its nice there is over 100 but there is no balance to them at all. And I mean at all, you have champs tower diving at level 2, killin you, and getting away alive. In a game a lvl 3 champ did charge attack to reach me and in 2 hits I was dead, no champ should be able to do that at lvl 3. Its too bad cuz some of the champs seem cool but with no balance who cares.
Just an FYI: You can go into settings and find Network Quality, its default is High, change to Low....you can play a few minutes that way before you end up disconnected regardless; least you get those few minutes.