Before the rise and fall of Angry Birds, Rovio produced a number of Java phone games, of which the shining jewel (or darkest void?) was undoubtedly the Darkest Fear series.
Hybrid survival horror puzzle adventure games with a genuinely haunting atmosphere, the Darkest Fear games all have a top-down isometric perspective as you navigate the map and static or lightly animated photobashed cutscenes. The primary puzzle mechanic ties in with narrative themes of (literal) darkness and light as you use illumination puzzles to safely traverse each level, save other inhabitants from a mysterious virus, and confront what nightmarish creatures may lie waiting in the dark.
There's also a bit of light sokobanning as you punt crates and rocks around to clear paths, and a handful of action sequences involving those mechanics and rather more dodging that one would necessarily like, but they're mercifully rare and the games' difficulty curve is generally pretty casual.
The first game begins at a hospital that has been plunged into an eerie darkness. Thomas Warden is summoned to Grim Oak hospital by his wife, a doctor there. He finds the place plunged into darkness, deserted by its staff and, soon, haunted by hideous monsters. At a couple of key points, your choices and the equipment you carry make a difference to how the plot unfolds and who you can save.
Set five years after the first game, Darkest Fear 2: Grim Oak gives you more monsters to evade and more light sources to take advantage of. More significant object puzzles have been introduced, adding adventure game elements to the proceedings. You finally get to leave the hospital and explore the entire town of Grim Oak, and the world is relatively open, giving you some choice in the order you explore in.
The final instalment, Darkest Fear: Nightmare, introduces a second playable character who might cling to the darkness for safety as fervently Warden must keep to the light. You can switch between them to tackle puzzles suited to their unique skillsets, and, as the overarching series narrative concludes, a total of 15 different endings can be achieved. The third game uses some particularly nice lighting effects and generally more polished graphics.
Although the first installment was available on iOS for a while, the J2ME edition can safely be regarded as definitive. You can and should treat these as closely successive chapters of the same game. Although they deal with horrific themes and bear a Mature rating, the stylised graphics leave most of the unpleasantness to your imagination.
The entire series combines a sometimes janky, yet atmospheric, plot with some genuinely gratifying puzzles, solid level design, and excellent use of their target devices' limited graphical capabilities. They play nicely on modern Android devices thanks to J2ME Loader.
You can still watch the 2006 trailer for Darkest Fear 3 on what is now the official Angry Birds channel.