The game seems okay but a lot mechanics don't really work for me.
First of all there will be INSANE amounts of grind, absolutely insane. Each stage seems to have 10 levels, each level has 5 objectives to complete, three of the five objectives require specific dragons and items to be completed so you will more than likely have to buy them with real money if you want to complete the objectives.
The reason you might want to complete the objectives is because they will give you rewards (like a new dragon if you complete all 5 objectives in all 10 levels, so 150 total "levels" * an average of 7 minutes per level = 1050 minutes/17.5 hours total assuming you finish them all in your first try, which you wont)
. Again, this is a huge grind if you want to do the single player missions to try and get new dragons or items or whatever else they may give you.
Game difficulty seems to ramp up very quickly as well. I'm barely on act 1-5 (undead crypt?) and it's pretty much impossible to complete with all the dragons they throw at you. I opened one door and 5-6 very powerful dragons spawned. I used all 3 revives and still wasn't able to kill them.
I haven't kept track of how much money you get per completed mission but it's very very little. Half way done with "act 1" and I only have about 400 gold or whatever the currency is. To purchase a dragon pack (3 random dragons) you need 5000, to purchase weapon pack (3 random weapons) you need 2500 I believe. Steam says I've played 2.2 hours, remove about 15-20 minutes to account for the tutorial and you can see how slowly you earn money.
The microtransactions SEEM pretty reasonable compared to other games but I haven't spent too much time looking at and comparing everything. Some dragons are 3-5 dollars which isn't bad.
The mechanics that don't work or that I'm simply not a fan of is the movement and combat. Most of the time it's just a huge mess of enemies clustered together flying around each other trying to hit you. My only recommendation would be a complete overhaul of the controls where you use WASD (or whatever keys you bind) to move and have the dragon shoot where your mouse cursor points (restricted to 140-180 degrees of the direction you're facing, otherwise it would just be silly). Whether the developers are interested in putting all this work to change it, I don't know.
Options are terrible. I wanted to lower the volume and you can only toggle both the sounds and music on or off. You can change your resolution and that's about it. It feels like a really terrible mobile port or browser based game. The game has potential with the idea but it's not really worth investing any time or money into at this point. It is free though so by all means try it, but if you have bandwidth limits or something then I wouldn't recommend it (although it's only 300ish mb which is nice).
If the grind is lessened and the controls are done better I think it would definitely be worth investing some time into. I have not played the PvP yet so any sort of balance or matchmaking issues are obviously not covered in this.