Lost Mars is a side-scrolling action-adventure game in which an astronaut named Liang descends into the lava tubes beneath the surface of Mars, searching for lost predecessors while also carrying on their mission of discovering life. Yes, in this game, there is life on Mars -- and it's all plant-like. An AI companion (who helps you out by telling you about your surroundings) informs Liang early on that the lifeforms aren't exactly classifiable as plants, but they're all certainly plant-ish. They might move around, or take insect-like forms, but they also grow out of grassy patches in the cave walls and spit out seeds that you can plant by throwing them into said patches.
This is the central mechanic of Lost Mars -- what Tiger Style called "action gardening." In order to pass gates within each level, you must achieve a certain amount of "biomass" by planting seeds, which grow instantly. The first plant you encounter does nothing but grow; later, you find plants that produce water, causing other plants nearby to produce more seeds.
Other plants act more "creature"-like, and were shown to grab seeds out of the air to eat, or even eat other plants nearby. There's a puzzle aspect to generating enough of the right kind of seeds to produce enough biomass. But there's also a pseudo-platforming element to Lost Mars, as you have to jetpack your way through the winding caves, doing your best not to fall too far and hurt yourself, or land in a pool of lava. Movement is extremely streamlined: you just touch the screen to point to where you want Liang to go, and there's no limit on your jetpacking. So it's not a very technical platformer. It's more of a platformer feel.
Despite claims that some of the art in use was placeholder, Lost Mars was already stunning, with an effective foreground parallax effect that saw rocks scrolling by in the "front" of the screen; it looked eerily like staring into a deep cave. The art must at least be close to complete, as during the Juegos stage presentation, lead programmer David Kalina said that Tiger Style was "trying to get the game out the door by Halloween."