Deus Ex Go is the third game from Square-Enix using the 'Go' concept of turning another franchise into a smaller puzzle game with settings and elements from the original products. While Hitman Go had more of a board game aesthetic, Lara Croft Go started going in the direction of representing more of the Lara Croft universe and Deus Ex continues to go in that direction. I had fun with this game, although on my iPad 3, it was a bit laborious to play. I got to the end of the game and while I didn't 'master' every level, I felt it was a good balance of fairness and complexity.
The way this game works is that you play each puzzle board with a clear destination. To get there, you need to evade dangers and traps, either by defeating enemies from the sides while they're vulnerable - some foes, like armored guards and turrets can't be defeated - or by using tools at your disposal on each map. Things like turning invisible for a few step, or hacking turrets and map tiles at your advantage. Each level is a well crafted puzzle with a very small number of 'right' solutions, and you get a gold medal if you complete it on the optimal number of turns. Sometimes it can get frustrating if you don't see the solution, but the game gives you a fair number of 'undos' you can use if you get stuck or make the wrong move. There are also consumables to solve a level for you, and I used one once to see how it went. You can buy more with in-app purchases.
The only small issues I've had with the game - besides the performance, which I can blame on my hardware - were some small parts of the controls. I enjoyed how you could swipe anywhere on-screen to move Jensen around and I used that more than tapping on my desired destination. That being said, when it came to using the hacking terminals or the invisibility power-up, you still have to tap on the icons placed on the map or at the corners of the screen. I kinda wish that you would have a way to execute all actions only by using a small unused spot of the screen where you're already swiping to move around.
But besides that, I have nothing negative to say about Deus Ex Go. It's a good puzzle game and its roots in the Deus Ex universe are giving it a nice sci-fi setting. There are plenty of mechanics and enemies that appear as you go through the worlds of the game and you can always go back and try to perfect them. The in-app purchases aren't overwhelming at all and the whole package is well worth it.