I had plans for a highly productive evening yesterday, then I discovered Blockoban [App Store], a simple block sliding game that not only is a ton of fun but also serves as an excellent example of a free trial that is upgraded to the full version via an in-app purchase. Blockoban is the latest game to make its way to the iPhone from developer BonusLevel.org's array of free flash games, the first of which was Moonlights [$1.99 / Free], a structure building physics game we enjoyed in our review.
Like any good puzzle game for the iPhone, the core gameplay elements are both simple and approachable. Controls are implemented well utilizing standard swiping gestures to move pieces around along with pinching gestures to zoom in and out for more precise control-- A feature which becomes vital in the later levels which are much larger than the easier ones.
An in-game tutorial walks you through the concept behind the game. On the simplest levels, you need to slide blocks of different colors in to the spaces on the game board with corresponding colors. When you slide a block, it moves until it collides with something, and levels often require quite a bit of planning as you figure out where everything needs to be moved and in what order to end up in the correct positions.
As you progress through the game, new block types are introduced that behave differently and require new strategies to deal with. Meanwhile, every move you make is tracked and optionally uploaded to the Plus+ powered online leaderboards along with whatever achievements you managed to earn along the way.
A solid puzzle game with colorful graphics, good music, and fun gameplay would usually be a slam dunk alone, but Blockoban takes things a step further with the implementation of many more small features which combine in to a game which far exceeded my expectations.
First of all, Blockoban is completely free to try. There is only one version of the game to download that includes both the tutorial and a pack of 100 free levels. If you make it through that and want more, a pack of an additional 820 levels can be purchased inside of the game for $1.99. Optionally, if you're stuck on a hard level you can buy the solutions pack for another $1.99 to watch levels get solved move by move.
You have unlimited undos, and I've yet to find myself in a situation where I just need to completely start a level over as I can quickly undo to before things started to go pear shaped. Blockoban also saves exactly where you are when you quit the game (a feature more games need to have) and if you use Plus+, your game state is also saved online, synchronizing your saved game across any device of yours that is also logged in to your Plus+ account-- Another particularly handy feature especially if you own both an iPhone and iPod touch.
If you somehow manage to make it through the 920 different puzzles, each of the five difficulty levels also include a "map generator" which whips up a randomly created puzzle for you to solve. There's even an online level editor where you can submit levels that are then reviewed by the Blockoban team for potential inclusion in to "official" level packs.
Blockoban is a lot of fun, and the single free version that is unlockable to the full version does a great job at making sure you enjoy it and know what you're getting in to before you buy it-- In fact, you aren't even given the option to upgrade until you've completed the tutorial. If you like puzzle games, you need to give Blockoban a shot. If you're a developer, it's also worth a peek to see a really great implementation of a free to paid in-game microtransaction system.
App Store Link: Blockoban, Free
(Fully unlocked game, $1.99 or $3.98 with optional solutions pack.)