All too often in iOS games, progression feels like a chore. Knightmare Tower reminds us that you can have a quick-play experience with an upgrade tree that's not only enjoyable, but lets you advance by diving sword-first onto the heads of spiky blobs and dragons.

You contriol a rocket propelled knight who must ascend a tower to rescue a series of captured princesses because videogames. Unfortunately, the tower to which these lovely ladies have been taken is as tall as it is perilous. To rescue each subsequent princess, you need to reach a certain height barrier. You gain boost and momentum by kiiling beasties, which you can attack by tapping on the screen. Tilting your deivce steers your knight left and right, allowing you to dodge projectiles and line-up your swipes.

Though you need to keep killing to continue rising up the tower, you'll need to temper your bloodlust with caution. The tilt controls are responsive, but it's very easy to overshoot your target. Usually, missing an enemy just wastes time. Waste too much time, however, and magma will start to rise from the bottom of the screen. You also need to keep an eye on your health, as nasties will fire plasma balls or reveal deadly spikes just as you go in for a killstroke.

Upon death, you'll most likely have enough money to purchase new upgrades from the store. These include new weapons and armour, items like oil to lessen wind resistance, or potions that aid you in your ascent. The game dishes out cash at a respectable rate, and we were generally able to upgrade something after every session. Rescuing princesses unlocks more bonuses, too.

While working on your targeting skills is a challenge, the game's compulsive dive-bombing core and rewarding upgrade system kept us glued to our screen for the duration. It's a little short, and takes a few upgrades to really get into its stride, but we reckon that this is one tower that's well worth the climb.