20$ for all heroes? Thats, pretty darn unlikely. Considering they're 5$ a piece and 50 of them.
Gah! Demigod had FAR less depth, far less gameplay variety. True, league of legends does not allow you to upgrade your units/towers, and has 1/2 the maps (2 instead of 4), but it fundamentally focuses on "you" as a hero, and less on what your minions are doing. There is more to do as far as choosing between fighting NPCs (creep-ing it is called, killing the neutral units), or skirmishing in your chosen "lane", or fighting enemy heroes.
In demigod, the non-hero units were either cannon fodder, or stronger than the heroes themselves. This made it nearly impossible to turn-around a loosing situation, since it was all about how well your NPCs were upgraded. In LoL, you can turn it around quickly if you kill the enemy heroes several times (or if you manage to kill all of them at once), since you get so much bonus gold for doing so, and are so powerful compared to the NPCs in the mid-late game.
Also, LoL has character progression, and talent-trees, and "runes" for equipment that you manage between rounds, in addition to more in-game items to choose from and more complex item upgrade trees.
I'm really just surprised you said Demigod had more depth, since in my view it is a extremely limited (both in innovation and options), extremely small-scale game compared to LoL.