Many upgrades and game features are locked behind online-required DRM, violating GOG's alleged principles of being DRM free.
I got this on steam, so I cannot speak to any technical differences that may exist between the GOG version. The combat is simple, and mobilitiy is good and air controls never fail or feel clunky. Much like rogue legacy, you get gold on each run that can be used to unlock what amount to classes and unviersal upgrades. Random powerups/modifiers exist in scrolls, and can have good or bad effects that change gameplay. I had a hard time stopping a session, always wanting one more playthrough.
