Watered down, uninteresting version of King's Bounty: The Legend and its nice sequels. This started as Facebook game (which is where I tried it initially, long enough to see all the features) with microtransactions and a wait-or-pay-to-play system. Facebook login is not required to play unless you want any of the sharing features or cross-platform play with browser and mobile. Typical for this kind of game, you can expect constant "share this with your friends!" prompts and an unskippable mission to send gifts to friends, and so on.
The combat system isn't as interesting as the true King's Bounty games: gone are the three hero classes and the skill trees. No mana management, you have to purchase scrolls for each spellcasting. You don't lose troops, you just pay gold to resurrect them. Units can always move their full movement and attack or fire. Units are missing some interesting abilities they have in the "real" games. Side-note: animations are also inferior-looking and don't have the wacky character of the originals.
The overworld map shows its flash game origins and is a far cry from the gorgeous 3D maps of the original games. The quests are given in the usual dry facebook game style, and I haven't detected the trademark humor of KB:TL either.
Only redeeming factor would be maybe the presence of a PvP option, or the simple progression system which allows you to upgrade the stats of your units, as well as a simple crafting system.
Overall unless you're really interested in the social aspects or you're desperate to play this on your phone, I don't see a good reason why you'd play this instead of buying King's Bounty: The Legend. If you don't have it yet wait for the next bundle where you'll be able to get it for under 4$. (Google the "Wars of Ages" bundle for instance, should be up until mid-january 2013.)