In the years to come, there'll be one overriding memory of the iPhone era: the ability for simple ideas to be transformed into truly addictive experiences.
A cursory look at what's involved suggests the game ticks all the right boxes when it comes to delivering a simple concept, although design issues prevent it from being truly memorable.
Creatures & Castles is a collection of 2D mazes in a medieval setting, the idea being to navigate through each stage to reach a gate on the other side in one piece. You do this by drawing a path from entry to exit, then tapping your treasure hunter - either young lad Timmy or wee lass Susie.
You receive more points for using the shortest path possible, - the ideal being to reach the gate in quick fashion, without any stopping or stalling - although timing is arguably the most crucial element, given the levels are populated with an array of sentries eager to halt your progress.
All such foes follow set paths, making success a question of observing their movement before navigating past them. It's stealth at its most basic and, for the first few stages at least, it's not hard to get involved.
Repeat and replay
Problems arise when you come into contact with any of the guards on patrol. Such failure resets the level, but your path is also erased in the process.
That might seem like a logical response, but often your demise had nothing to do with the route you mapped out, but rather when you chose to set it in motion.
Re-drawing what's obviously the right path time and again simply because, somewhere down the line, your timing was out of whack is a bore, especially when you consider Creature & Castles has a habit of misreading your input entirely when you near the goal.
At times, the game refuses to obey your commands, the icon drawn away from your chosen route as if by a magnet.
Yet, it's the sheer complexity of the stages as you progress - bombs, for instance, have to be picked up and planted to blast through walls in stages where no clear route exists - that makes retracing your path multiple times grating.
Being penalised for the most menial of mistakes feels less like a stiff challenge and more like the result of a game design and user interface that's needlessly unfair.
It serves as perfect evidence of the Creatures & Castles' rough, unpolished nature. The concept is a solid one, but the slack delivery means this is a fortification built on decidedly shifting sands.