If you've spent any time gaming on the PC or even major consoles it's hard not to have come across Orcs Must Die, Robot Entertainment's third-person take on tower defense gameplay. Now iOS gamers can experience a taste of the developer's whimsical sense of fun thanks to their free-to-download tactical title, Hero Academy.

Part card game, part turn-based strategy, players pit themselves against opponents from around the world in asynchronous matches. As such you can take part in multiple games at any one time, though nominally you'd like to be paired up with someone who's waiting to immediately respond to each turn, helping you to finish a game in a reasonable time.

Each turn players are given five actions, be it to summon a creature or item from their hand and in to the game field; move a particular unit in to a new position; or make a direct action such as combat, healing or summoning ghouls from the corpses of the recently deceased. Anything used from your hand is randomly replaced from a limited stock of reinforcements. While one of the victory conditions is to destroy the opponent's crystals, you could also find yourself facing defeat if you treat your items and characters like so much fodder.

It's tempting to push out too many units on to the field and this would be a huge mistake - given the limited amount of moves per turn you'll need to make the most of anywhere from 1 to 3 units. Any more and you start to limit your options and leave units open to retaliation. Despite the small amount of units at any one time the game feels immensely dynamic, with players being able to counter almost any situation given patience and resourcefulness.

However, being free you'd expect limitations and you'd be right - firstly access to the second available race (Dark Elves) along with access to aesthetic changes such as avatars, team colors and 'taunts' requires a cash purchase. More worryingly though is the lack of stat tracking for matches, making victories and losses hollow or devoid of meaning in the long-run. Players can see their recent matches, but it's a far-cry from climbing a competitive ladder and being matched with equally skilled opponents.

Speaking of which, it's also odd that the game opts to utilize Facebook for matching up with friends instead of more readily available solutions such as Game Center. Hopefully the currently implemented accounts tied in to Robot Entertainment's website result in better competitive features in the future.

Ultimately what you get with Hero Academy is what you pay for - a game with stunningly simple and refined tactical gameplay that is otherwise crippled by a lack of solid competitive features and no form of offline AI-based gameplay to keep you playing while you wait. I need more opponents, so I heartily recommend giving this game a go while it remains free.