This game has a map setup much like DotA, with creeps pushing through separate lanes towards an end goal - in this case the Citadel. A large part of DotA is pressure: gaining an advantage and pushing ahead to enemy towers by forcing opponents to retreat to their base. Another large part of DotA is resource and time management: deciding when to spend gold earned and choosing the most advantageous times to return to the base and buy items. Finally, a large part of DotA was knowing where to be at what stages of the game, and coordinating with teammates to that end.
To an extent, these elements are present in Demigod. However, the ease with which players can obtain health potions, mana potions, and teleport scrolls significantly lessens their importance. The sizes of the maps also play a role in lessening them, especially the last one.
The problem as I see it is that players are not sufficiently rewarded for pressuring opponents, as it is too easy to stay in a lane and maintain a push due to health potions, and it is also too easy for a player to teleport either to another lane, or to the main base and back. Returning to the base to buy items, get more potions and scrolls, and regain health, ought to have far more of a trade off than it currently does. Forcing somebody to leave their lane and fight in another should have more of an impact.
Without more cost or penalty for moving around the map or returning to the base frequently, players are not penalized for playing recklessly (for instance hard pushing a tower, teleporting back to base, regaining health, and then teleporting back). Players may say that the increased mobility allows for better team coordination, but cheap, low cooldown teleport scrolls and health potions allow players to fairly easily evade gang-up situations, which actually discourages teamwork. I have a difficult time imagining, for instance, seeing any of the kind of coordinated group "ganks" that are very common in DotA.
I feel I'm not conveying fully the negative impact that the ease of mobility and regeneration have on gameplay, but I feel that it is an important issue which ought to be addressed. Health potions especially ought to be, more than anything, emergency measures which cannot be used with much frequency. Teleport scrolls ought to have a longer casting time, and a longer cooldown. It is true that in DotA there are teleport items like the teleport scrolls in this game. However, it is not possible (if I recall correctly) to use them with the same ease and frequency that it is currently possible to use them in Demigod.
Finally, I would like to see maps be a bit bigger than they currently are, because this would again emphasize a players decisions in where to go and when; currently it's too easy to reach almost any point on a given map fairly quickly, so you aren't nearly as penalized for not being where you need to be. A response to this point may be that this ease of mobility quickens the pace of the game, but it also makes it much easier to play - it removes certain tactical elements from the gameplay. For example, there's not nearly as much use in trying to surprise or confuse your opponent with feints or sneak attacks if it's a simple matter of seconds to get from any one point on the map to another.
