Basic PC port
Some people might have been put off by the PC version of the game, which is a fairly low effort port. The default field of view is low (70, I believe) and there is no way to change it anywhere. You have to rely on 3rd party tools. I myself used Widescreen Fixer that worked wonderfully, though I had to first figure out what the game's default value was because the tool does not tell it, merely adds a desired amount to it.
Interacting with weapon and time manipulation device upgrade benches also happens with the enter and arrow keys -- the very thing I mentioned in my recent Alien: Isolation post about lazy ports. There are also no subtitles in the game but I doubt that is unique to the PC version.
That is where Singularity's gameplay problems end, however. It ran at stable 60 FPS for its whole length at super-sampled 4K resolution. The graphics are decent, pretty standard Unreal Engine 3 level, although the environments could have used more variation, in my opinion.
Familiar game mechanics
Weapons found in the game are also bog standard and offer no surprises, with maybe the Seeker rifle being an exception. The gun fires explosive bullets that can be guided during flight. It felt like a feature made for controllers but I did find it useful with mouse too at the docks map; I could cover the whole place just from the starting point.
Each of the weapons can be upgraded for more damage, clip capacity, and reload speed. The upgrade kits are sometimes hidden pretty well in the world and I probably missed a few. The game has a 2 weapon carry limit, though, so you do not really need to upgrade them all. And they work well enough without the upgrades too.
Time manipulation device, or TMD, brings something different to the game. It gives you few different abilities which include: moving objects and enemies in time (break/renew/damage) and place, a time stop bubble, and force push. In addition to its combat uses, you also need the device to solve puzzles to progress. They are, however, very simple and easy for anyone who has played through a game like Portal.
Fun but offers little challenge
The combat too was quite easy on normal difficulty. The only times I had to reload were when I stepped into electrified water by accident, took my time on exploring and let an important NPC die, and getting stuck on the second boss -- I did not understand what the game wanted me to do with the TMD once it locked to me to the monster. After a handful of tries I finally figured out I needed to use the double tap upgrade.
The most difficult enemy in Singularity is phase tick; a small, spider-like creature that comes in packs and whose purpose in life is to charge at you and then self-explode for lots of damage. Besides them, though, combat is fun. Enemies usually react properly to being hit, and well aimed shots drop them quickly. I wish there just was more of the game. Additional couple hours worth of combat would have helped greatly.
Singularity's plot is not terribly engaging. You play as a mute captain of the US Marines who is on a mission with his squad to investigate an old Soviet research base on an island in the Bering Sea. Things of course go wrong and soon your mission becomes to save the world. The time jumping probably involves plot holes like it usually does if you start thinking about it.
Surprisingly enough does Singularity also feature an ending choice -- three options even. I do think a straight up shooter, where you do not have to decide anything aside from how to engage enemies, really does not need a choice which cutscene you get at the end. Just slap a feel-good ending to it and call it a day, if you ask me.