Topware unleashes orc hordes onto iOS in Two World's II Castle Defense

Presumably the main difference between tower and castle defence is an issue of trademark legality.

But while Topware's Two World's II Castle Defense is all about defence, the focus of the action is characters, not buildings. After all, this is a game set in the developer's RPG Two Worlds PC universe; indeed these iOS versions are based on the PC game of the same name.

So, it's a typical humans versus orcs, scorpions and skeletons etc affair, plus the usual amount of strange names - you take the role of the Emperor Gandohar and his henchman Sordahon in the world of Antaloor.

In terms of the gameplay however, your mission is simple - to protect the Emperor from the enemies waves out to destroy him.

As per usual, you're balancing your gold reserves with buying new units and upgrading existing ones. You don't have any direct control over the combat, although you can teleport troops between pre-defined locations, also concealing/revealing them. You can also actively heal and resurrect them, or if they're in range of a priest, or standing on their spawn point, they'll regenerate automatically, if much slower.

Your main troops are split between melee swordsmen types and ranged archers, while necromancers will slow the enemy advance. You do get direct attacks too, which are linked to the Emperor, so if you level him up, they get more powerful and regenerate quicker.

There's a Campaign mode to play through, plus an arena-based quicker play mode, while Game Center and OpenFeint are supported for achievements and leaderboards.

It doesn't come cheap however. Two World's II Castle Defense costs $9.99 for the iPhone version and $11.99 for the iPad version, although there are free versions for both devices in which you can buy specific levels.