Your Dark Tower is your base of operations, and from here you teleport to the various realms in your demesne. When you start, your tower will be a wreck, but as you progress through the game, you'll find items that help you repair and improve your HQ.
When you rescue the damsel in distress (or datdress...), she'll take over the decoration of the tower for you and you can start to spend all your ill-gotten gold on interior design. I'd recommend ignoring her suggestions though and spending your gold on new weapons and armour as you find new recipes and combos.
There are four different types of minion at your disposal, each with their own abilities. Brown minions are your general purpose tools, which are also more resilient to attack than the other types.
Green minions are immune to poison, and are also very good at climbing on the backs of larger enemies to attack them more effectively. Red minions are immune to fire and lob fireballs at enemies, making them an effective long-range attack force. Blue minions are able to walk through water, but are very weak – however, they can also resurrect fallen minions, meaning that you don't waste life force.
Each minion is created via a summoning pit in the ground, with different coloured summoning pits representing different minion types and brown pits being both the most common pit and also an excellent chance for an off-colour joke.
The number of minions that you can summon in total is limited by your available life force: each minion type has its own life force type, which is given up when you kill some enemies or smash some crates.
You start off the game with only brown minions at your command. You'll have to explore several different realms to find the other three minion types, meaning that you'll have several region missions on the go at once as you reach an obstacle that requires a minion type that you haven't found yet. This keeps the interest up, and means that the game doesn't follow an obviously linear play-through.
As you wander round the different areas of your domain, you'll come across various objects that enhance your power in some way: new spells or spell upgrades, maximum health or mana increases, armour or weapons recipes or an upgrade to the maximum number of minions you can control.
The one major downside with Overlord: Raising Hell
is the control method, especially camera control. Since you use one analogue stick to control the overlord and the other to control the minions, there's no stick left to control the camera. This is particularly frustrating when you're trying to control minions from afar, as the camera stays resolutely stuck behind the overlord's shoulder. This makes minion control quite awkward, something that's quite important when you're using them to attack a distant enemy.
Combat is also a decidedly one-button affair, although it's rare that you'll be using the overlord in direct combat – that's what the minions are for, after all. Combat spells are also difficult to target and it's often hit-and-miss.
Most of the time, the minion AI is fairly good, although sometimes it does make silly mistakes, such as sending brown minions through water when you call them back to your side – a decision which will result in their death unless you're particularly quick thinking. It's also not possible to leave one group of minions standing while you go exploring with another. Get too far from your minions and they'll vanish into thin air. Maybe they just get bored of waiting for you to return?