Pikemen first came out in 1997, which makes it one of the older pyramid games. (I personally mark 2006, when Treehouse came out, as one of the major milestones of the pyramid system) And, more than any other pyramid game I've played, it is the one that most closely resembles a classic abstract.
The game is pretty simple. Everyone gets a set of pyramids, made up of all three sizes (they come in big, medium and small, by the way) The number of pyramids and the board layout depends on the number of players. You can even use some quickly rhombus-shaped pieces for unusual numbers, like three players.
On your turn, you can do two different actions. You can align a pyramid, pointing it in any direction (including up and the diagonals) or you can move a pyramid. Pyramids can only move in the direction that they are pointing and realign after they stop. They can move any number of spaces but they can't jump over another piece.
But they can capture. You can capture any piece if they are on their side, in the moving and attacking position. However, if a piece is pointing up, it is defending and can only be captured by a larger pyramid. So a big pyramid that's pointing up can't be captured at all.
Every captured pyramid is worth points, one to three depending on their size. The first player to get to twelve points wins the game.
There are two rules that make a critical difference in the play of Pikeman (because games about moving and capturing pieces are pretty common but all too many aren't that good) First of all, being able to reorient a piece after moves is big. It effectively gives you two moves in one, which makes the game a lot more dynamic.
Second, you don't play until someone runs out of pieces. You play to twelve points. That definitely makes the game shorter than it would be and it also helps make it more dynamic. Pikemen isn't about defending. It's about attacking.
Like I wrote earlier, Pikemen feels like a much more traditional game than most of the games in the Looney Pyramid system. If someone told me it was adapted from an earlier, nineteenth century abstract, I wouldn't be surprised. It's also not the kind of abstract that I personally go looking for. After I got into Go, I've been more interested in abstracts build around placement than movement.
All that said, Pikemen is a solid game. It offers plenty of choices and surprisingly dynamic play. Not every pyramid game has to invent a new kind of wheel. Some can just offer good play.