Interesting Concept, Flawed Execution
Unfortunately, there are some significant execution flaws. Mindjack is a cover-based shooter, meaning that, more often than not, you're either in cover, taking a quick break from cover to shoot someone, or moving as quickly as possible to another piece of cover. To this end, the "take cover" button is the same as the sprint/roll button, meaning that you can sprint up to a suitable object and seamlessly take cover behind it.
Unfortunately, the game has a rather broad definition of what constitutes "cover": A wall seems to always be considered "cover" regardless of which way it's facing. This can result in some frustrating moments where you sprint across a hall to take cover in an alcove, only to discover that you weren't aligned quite right when your character plasters themselves against the exposed corridor wall while several enemies with machine guns open fire.
The titular mind-jacking ability is fairly good at turning the tables in a firefight, since you have the ability to "hack out" of your current body and float around to find a suitable target to take control of, similar to Geist (although without immediately killing your current host). Time continues to run while you're in "Wanderer" mode, but an AI takes over your body while you're out. The AI does seem to like to shoot things, meaning that if you leave your body while in cover, you really can't expect it to stay there. This can be problematic because the game ends if both main characters are disabled.
Which brings us to yet another issue: Time NEVER stops. And I mean NEVER. Mindjack features the ability to play in "Host Mode", where you control the main characters and advance through the story, or in "Hack Mode", where you spawn into someone else's Host Mode game either as a Wanderer on their team or on the opposing side. Because of this, you can't actually pause the game: pressing Start brings up the menu, but the game continues to play in the background while your character sits there. Although there's a "Hacker Limit" option to disable having other players jump into your game, you still can't pause.
The game also only gives you a few seconds between stages to select whether you want to continue on to the next stage or return to the main menu, which means that there's no real downtime to take care of anything you need to do in the real world. If the phone rings, or you need to take a break mid-stage, expect to have to restart the stage from the beginning.
It's not all bad, though. Besides mind-jacking cowering civilians (who, for some reason always seem to be armed, sometimes with machine guns, although police officers seem to be limited to handguns), you also have to ability to mind-hack disabled enemies to have them get up and fight on your side (either until they are killed or until you mind-hack someone else). For this reason, it's not always best to outright kill enemies, since the temporary support can make all the difference (even if they have the nasty habit of strafing into your line of fire). You must be in relatively close proximity (I think the game says something like 15 meters) to mind-hack, so you have to balance the safety of staying in cover against the need to be close enough to mind-hack a fallen enemy and turn him against the other guy in cover next to him.
Overall, Mindjack is a fun game, if you can overlook the flaws. While some encounters can be very frustrating, and the game doesn't seem to have a checkpoint system between stages, the game does reward perseverance in the form of XP awarded for each kill. Collect enough XP, and you "level up" as in an RPG. While there are no immediate effects, certain level thresholds unlock "Plug-In" features, which allow you to tweak aspects of the game, such as improving character abilities slightly or changing the difficulty level. Still, it's not a game for the easily frustrated.