One reason Blokus has been such a hit in the board game community is that the gameplay is fairly simple. Each player starts with the same set of Tetris-like pieces that they need to fit onto the board. You need to grow your network of tiles bit by bit from your starting location (either from the corner on the original board or from a more central starting location on the two-player board). The catch is that you can't put any piece orthogonally adjacent to your own pieces, which lets you expand quickly but leaves a Swiss-cheese-like mess in your wake. The goal is to prevent your opponents from placing more pieces than you do.
It's hard to really cut someone off in the beginning of the game because those diagonals allow for a lot of maneuvering. Good strategists will quickly learn to place their pieces in such a way that their opponents need to make some real tough decisions about which tiles to try and fit on the board and which ones to give up on, and this is what makes Blokus so appealing. Games last maybe 20 minutes, but they're way faster on the iPad.
Blokus HD not only includes the original 2-4-player Blokus, but also the two-player version on a smaller board called Blokus Duo (also Travel Blokus), so there's a lot of gameplay variety included in one purchase.
Aside from implementing the Blokus gameplay flawlessly, the app also imports a few devices from video games (i.e., achievements) that give you more reasons to play repeatedly. Some are easy – starting a tournament game, for example – some are quite difficult to do and win – playing all your pieces from largest to smallest – so there's a nice skill level ramp to climb. Each turn, the pieces you have left appear at the bottom of the screen and little triangles flash on the board in the spaces where you can still play a piece (oh, how we wish we could turn this "feature" off). You tap the piece you want to play, maneuver it into position and tap the green checkmark. Wait a few seconds for the AI to place the other pieces, then take your next turn. In a multiplayer game with the iPad laying flat on the table, it's best to rotate the iPad to the person whose turn it is, because the piece selection is always at the bottom. Also, when it's not your turn, you can't see your pieces and plan your next move when playing in hotseat mode, which is too bad.
There are two great features built into the app, one that works well and one that doesn't. Feature 1: you can pause, skip and rewind your iTunes music without exiting the app by clicking the little music icon on the bottom of the screen.
Feature 2: the game has a colorblind mode that overlays little shapes on the pieces to make them easily distinguishable from one another. The screen looks way too busy with them turned on, but if they're needed, it's great to have them as an option.
Now for the bad stuff. That iTunes feature? It doesn't work all that well. If you pause an album, there's no guarantee that it'll start back up when you unpause the music. Oh, and if you don't like flashy apps, this one gets annoying fast. There are lots of "Great block!" encouragements and shiny wipes that wash over the screen, and everything is brightly colored and shimmery. Sure, this kind of mimics the bright plastic colors of the tabletop version – props to Gameloft for keeping it real – but it'd also be nice to tone some of this down a bit. We don't need it to be as plain as Pathology, but a little less bling can be a good thing. Also, Blokus HD doesn't always save your game when you leave the app. Booo.
Another major problem with Blokus HD is the game's unresponsiveness when trying to rotate a tile. The app lets you spin them by either putting your finger on the circular outline that halos a piece you're about to play on the board or by using two fingers on the smaller representative piece in your play area. Either way you try, it doesn't work well at all. This is something you need to do multiple times each game, so the "God, that's annoying" factor climbs real high, real fast. With so many coders and testers contributing to the game (something like two dozen people worked on quality assurance, for crying out loud), this shouldn't happen. Especially not in a $5 app.
The Blokus apps also allow three humans to play Blokus, something that you can't do (totally fairly) using the tabletop version. With the computer handling the duties of controlling one or more of the colors (and yes, the extra player AI can be set to different skill levels), three-player Blokus is finally possible without investing in a Blokus Trigon board. Speaking of which, why isn't Trigon an option in this app? Seems like it should be – which means we'll probably see it as either an in-game purchase or as a separate app somewhere down the road.