I purchased the starter pack but I wont be buying anything more until you give a little more to the players. I used gobs of CE crafting 3 star equipment thinking it would make a large difference and let me play without dying all the time. But because of the way you've throttled the damage done based on the tier that your in, I still die frequently even in tier one. Part of the enjoyment in an RPG is feeling like their is some kind of progression in your character. Investing a bunch of time and money (actual money) into a character and finding out it's still weak destroys whatever enjoyment new players briefly felt in your games general design.
The way the game plays right now, you can only play for a short time. And you can only do that if you are willing to run from enemies all day long. If you like to play like a tank, you're going to get less than ten minutes of play before you burn through the 100 energy provided for free. This has to be fixed or I and I suspect many of the 1,000,000 players you managed to get with the F2P model will never come back. Here are a few ideas:

1) You could add a new type of energy that can only be used to open gates and revive, and give players significantly more of that. Then keep the CE the same and require it to craft items.

2) You could open the weapon damage up a little more. Stop throttling it on lower levels. If I hit a tier 1 enemy with a sword designed to be used in the second tier, they should just die. In every RPG I've ever played when I level my character to level 50 I don't get killed by the little slimes found at the beginning of the game.

3) Make healing items drop more frequently. Put the healing heart regeneration squares at the end of each stage, or every other stage at least.

4) Give us more health bars, make armor that is leveled up have more health bars, in a more generous fashion. I've been playing for 20 hours and I have a character that has almost the same number of health bars that I started with despite having three star armor, helm and shield.

5) Decrease the cost of CE.

6) Give more energy per day, or decrease the cost of opening gates and reviving. Having the cost of reviving raise exponentially with each death is a little much don't you think.

7) How about giving a weekly aliquot of energy? You raise the limit to 700 mist energy and give it out at a set time of the week instead of slowly regenerating.

8) Or keep the 100 mist limit, and make it regenerate in about 6 hours.

I think the base game is an enjoyable experience and the earliest level. I gave the game a try to get the TF hat. I liked it enough to buy the starter pack, thinking it was a similar amount of money to what I would spend on a game I liked in the store. But the longer I played the more it felt like a game just designed to nickle and dime me for cash. I'm willing to pay, but you have to offer something in return. I recognize that there is a balance in keeping a game challenging enough to keep it interesting and making it too hard. The way you have it right now feels broken.