BE-a-St is a game about reincarnation. You have to play as every beast by unlocking them to become a Saint. It's currently only in the concept stage.
Basically, gameplay would involve taking control of one creature and exploring the environment using its various skills; some could fly, others could swim, or dig, or move rocks, or climb, or even talk or wield equipment. But this creature would have limited HP and a lifespan, and once your health was down (there'd be a lot of predators) or your time was up, you'd die and go to Heaven.
Once here, you'd find your way to the Afterlife blocked by a gate which you're told won't open for you unless you are a Saint; a title earned only by those who have sufficient life experience.
So you need to go back down to the physical world, to reincarnate in a new life, but the thing is, you can incarnate as any other lifeform that you'd unlocked and the gameplay would be different for each one. You'd solve environmental puzzles by incarnating as many different lifeforms.
The game wouldn't focus on difficulty like Raider, but ambience and the thrill of exploration. The game would be low on text or explicit GUI features, to hopefully give the sensation of playing as a mindless animal.
Pseudolonewolf's going to release a simplified version of Be-a-St with limited features, and if it's popular he'll develop an in-depth sequel.