At the time, a lot of my experience with Looney Labs have been through Fluxx and Aquarius. Which are still games that I do enjoy but the pyramids and Martian Chess definitely opened up a different side of the company to me.
Fluxx is, of course, a very random game and Aquarius, while it is solid, is still very light. Martian Chess, on the other hand, is an abstract with no random elements whatsoever. It has some definite depth and strategy.
I did a fairly detailed review of the game about eleven years ago (https://boardgamegeek.com/thread/82875/game-changing-pieces-and-shifting-ground) but here's a general overview. You have three different pieces with different movements, up to the Queen who moves like a chess queen. Captured pieces go in your score pile with the most points winning.
Ah, but there's a clever bit and it's a good one. No one owns any particular pieces per se. Instead, you own part of the board and every piece on your part is under your control. (And, no, you can't capture your own pieces. Thanks for trying) So every piece you use to capture then belongs to an opponent.
Oh and there are a wide variety of board layouts to accommodate different numbers of players. Personally, I prefer a simple four by eight two-player game but it's cool how many options there are. The boards made out of rhombuses are neat.
All that said, the sparkle has worn off Martian Chess for me since I wrote that review in 2005. It became too easy for games to descend into almost null moves, making stalemates. (I have read suggestions on how to deal with that, including the first player to eighteen points winning, since they have the majority of the possible points and will win anyway)
I also got into Go which changed my tastes in abstracts. I came to like stones on the board with the flow of the game always mov my forward more than moving pieces.
I also went on to learn other pyramid games that are, quite frankly, better. Volcano, as a clear example, is another pure abstract that is a better game and makes better use of the unique nature of the pyramids.
Still, Martian Chess is an interesting game. Players owning the board, not the pieces is a very neat idea. And it did help me get into the pyramids, which has never stopped being rewarding.