Kids build forts; it's just something they like to do. Grab any old thing and put it on top of something else until you've got a big enough structure to hide in and you've got hours of fun. As an adult you don't really get to build forts though, unless you happen to be playing PixelJunk Monsters, the PlayStation 3 strategy game for the PlayStation Network that's now been ported across to the PSP. Here you build fortified weapons out of trees - and then you dance inside them.
The premise of PixelJunk Monsters is incredibly simple. You play as the defender of the forest and it's your job to protect the innocent people back at base. The problem is that there's always a horde of monsters coming your way (10 waves per level to be exact), keen to get their evil hands (or teeth) on the cute little guys. For whatever reason you're useless as far as being an attacking force, but you can construct weapons atop towers.
At the start of each level (all fights are fought on a single game screen so there's no scrolling) you're given a certain number of coins and left to get on with the job at hand. The coins are used to build weapon towers, knocking down a tree in the process, and the incoming threat is shown at the bottom of the screen, so you have an idea of what type of enemy is coming up next. And the type is vital in how you go about taking it down.
Early on you'll be able to place basic arrow and cannon ball firing weapons, able to take down the ground units with relative ease, wandering round and picking up the dropped coins and gems like you're strolling through the park on a sunny Sunday afternoon. You use the collected coins to build more weapons and use the gems to upgrade those weapons and everything seems great. All your little guys are safe back at base and life couldn't be better. But then a wave of air-based enemies turn up.
PixelJunk Monsters is all about being prepared, and as much as this element keeps you on your toes it's also the cause of many problems. Even if you've managed to look ahead and build some air defence weapons, you don't know for sure which route through the map the enemies will take. While you can run around dismantling weapons and building new ones, if you've got to race the enemies across the map and build something in order to fend them off, chances are that a good number of innocent little guys waiting at base will be lost.