Thanks for playing!
2- The game IS made in Gamemaker 1.4, so it might be a bit slow on low-end laptops and the like (Gamemaker has made development a lot easier, but it isn't exactly known for its speed). I've tried to make it as efficient as I can, and I'll continue trying to make improvements so that hopefully the launch version will be a bit lighter.
3- I might still tune the "regular" fights to make them a bit faster before the final release, based on feedback and such. But I'll probably wait until I finish making the rest of the characters before doing any drastic game-wide adjustments. As for the Magnus Attacks, the demo only goes up to stage 3! So look forward to some more difficult ones in the full release.