Given Activision's apparent tendency to heavily promote everything under the sun that it publishes, it's a wonder that Singularity seems to be flying under the radar of so many people - including yours truly. I remember seeing clips of the game a while back, thought it looked mildly interesting, and then heard nothing more ... until it was practically on my desk.
It's even more surprising that it's actually pretty good.
Singularity puts the player in the head of special forces operative Renko, sent as a member of a squad to investigate a mysterious Cold War-era Soviet installation that has been emitting heavy pulses of radiation. It turns out that the radiation is the result of Soviet research on the powerful and unstable element E99, which caused a disaster that led to the abandonment and burial of the plant - only, an incident involving you accidentally triggers an alternate future where the Soviets won the Cold War thanks to the power of the aforementioned E99. Naturally we can't have that, so your job is to slip back and forth between 1955 and 2010 to set things right.
The upside to a world in which the Soviets defeated the Western powers with super-fancy technology is that they made some really neat guns that you get to take from them - and use against them. While the arsenal seems pretty old-hat and run-of-the-mill at first (pistol, shotgun, assault rifle), it starts to get more interesting when you get the sniper rifle that slows down time. It gets a lot more interesting when you get the Seeker, a gun that shoots a controllable, explosive bullet.
The Soviets didn't just make guns, though - they made the Time Manipulation Device, which you retrieve fairly early in the game. This little glove is the core of Singularity, and it is by this device that the game is made or broken. Initially, it can only shift things forward or backward in time and send out a damaging pulse of energy, but it gets upgraded over time to something akin to Half-Life 2's iconic gravity gun, only a bit less versatile.
While you can use the TMD as a weapon, it's more of a puzzle-solving tool. Restore this broken staircase to its original, whole state. Age the safe (and the soldiers guarding it) into dust to retrieve the hidden items inside. Age a crate so that it crumples, wedge it under a mostly-closed gate, and then restore it to force the gate open letting you crawl under - that sort of thing. As you progress in the game, the TMD will be upgraded with some fun features like the ability to stop time in a bubble, which is used both in combat and in puzzles, and switching back-and-forth between your magic-science glove and your guns has a good feel to it after some initial awkwardness.
As you progress through the ruined Katorga-12, you collect pieces of E99 technology, which - upon meeting the right man - can be used to upgrade your character (and the glove) with blueprints you find scattered through the installation. It's a solid idea and it works well, but it feels like developer Raven Software just lifted it from BioShock without giving you any of the more imaginative powers to be found in that game.