Okay, cool. Thank you for your replies. I've got a lot of in-store credit, plus the gift cards, so I'm not paying anything for the game.
Has anyone every used a trainer for a game that was downloaded digitally from Gamestop and have it succeeded? Any game?
GameStop's digital distribution service is essentially Impulse rebranded, so it's entirely dependent on the game as far as trainer compatibility goes. I would honestly say it might be better to only buy games that require Steam, if you're worried about GS.
Darksiders II is going to require Steam, at least - so I imagine there will probably only be one version of the trainer, which should work for you (and I). Pure speculation on the trainer since the game isn't out of course, as the game could unexpectedly require eighteen different always-on DRM processes running with built in anti-cheat measures.