This game looks very different from its predecessor. While in The Sentinel the levels were bright and colorful, in Sentinel Returns they are dark and gloomy, with flashes of light being emitted when an object is created or absorbed, and the mouse pointer dynamically lighting the world. The game has a general "hallucinated" look: the skies are made out of contrasting streaks of color; the trees look like sperms; the boulders breathe and have a sphincter on the top; the sentinels and sentries are hybrids of flesh and metal; the sentinel stands are covered with skin and have four vertebral columns protruding from the corners; the "specimen" representing the living part of the synthoid resembles a hydatidiform mole, and it squirms and lets out a shriek when injected with a needle.Wikipedia
Sentinel Returns supports only Glide as a 3D accelerator, and it has no software renderer either. If you want to play it on a PC with an OpenGL/Direct3D video card, you will need a Glide wrapper.
Success requires quick wit, good aim, careful planning, and the ability to deal with positional puzzles. It is very innovative, and incredibly addictive once you get used to the controls. The moody music (written by scaremaster John Carpenter) and eerie new-age terrain will grow on you after a while. Make no mistake about it, though, Sentinel Returns is a difficult game that might frustrate a lot of people. The player is rewarded for perfect moves: you gain advantage in later levels from not only defeating the Sentinel, but from how well you do it. Strategists who prefer reality-based games may have a problem with the abstract concepts in this game. Although the game's learning curve is isn't flat, anyone who enjoys real-time puzzles that require some hand-eye coordination will be able to quickly pick up the concepts. With over 650 levels to conquer and multiplayer options, Sentinel Returns will keep real-time puzzle meisters happy for a long time to come.