Most of the titles don’t have a problem, but some games don’t enjoy for certain memory addresses to be frozen, and they will subsequently crash. Like with any other trainer, there is the danger of crashing the game. It’s usually advisable to start the game from the trainer, if possible, but it’s likely that it will work even if you start MegaTrainer eXperience after the game is already running. Anyone can just install the application and run it. Using the application is anything but difficult. Trainers usually work by freezing certain values straight in the RAM memory when the game is loaded, so it’s not surprising that the developers managed to gather all of trainers for so many games in a single app. The guys who build MegaTrainer eXperience have a different approach, and they gather all the trainers in a single application, which they update all the time. So, if you want a trainer for XCOM 2, for example, you download that particular application. Most of the trainers that you can find out there are usually designed for a single game.
MegaTrainer eXperience is an application that gathers trainers for multiple games under the same roof, and it works very well for old and new titles.