Gameloft and I don't really get along. They used to release good Java mobile games back in the day, but after smartphones took off they released nothing but free to play or pay to win garbage. Sadly, this leaked over into handhelds a few times and the Vita was no exception. Injection is a dumbed down port of Asphalt 6: Adrenaline for mobile phones. A mobile game being directly ported to a handheld isn't the best of ideas and this game proves why.
With all of the pay to win aspects taken out of Asphalt, this is a rare opportunity to see how the game would play if all microtransactions and other cancer-riddled stuff is stripped out. On the surface, it's a reasonably accessible and playable racing game with licensed cars, more like a low budget PS2 title. The tracks are boring but work, with boost icons and jumps. The purpose of the game it to boost your way through the track as much as you can and take shortcuts. Once you fill your boost meter you can go into Adrenaline mode which allows you to easily knock cars off the road Burnout style and zoom ahead. I found the cars all pretty much handle the same, drifting is awful, and the whole game feels stiff and poorly made.
That's not to say there's zero fun in the game, it does work and is a nice mindless racer for fans of the series or anyone wanting a bargain bin racer on the Vita. Gameloft is not geniuses when it comes to handhelds as they don't work like mobile phones. Outside of career mode, you can race with other people (no one was even playing during launch don't worry) and there are typical event types to participate in such as elimination, time trial, and various others that have been done to death.
Injection is ugly, stiff, boring, and a slightly upgraded port of a mobile game that was already over a year old before the Vita was released. If you exhausted all your other racing option on Vita then go for this dead last.