The genre of 2D MOBAs that actually stay true to a strict DotA formula isn’t exactly bloated. Awesomenauts is one of the first games to make that leap into League of Legends meets Super Smash Bros territory paired with one of the best theme songs ever by Sonic Picnic. Unfortunately it was only available on XBLA and PSN originally, but fear no more. Ronimo Games has announced a PC version to be released on Steam “very soon”.
If you’re unfamiliar with Awesomenauts, here’s an in-depth developer commentary courtesy of Cynical Brit.