That is something that cannot be accurately predicted in advance - particularly as you can guarantee that the first release will be full of bugs. How bad those bugs will be will depend, at least a bit, on your particular set up.
I know a couple of people who've been doing a technical test on it, and have run some RPGMaker games on it without problems - but their advice to me was not to touch Windows 10 for at least 3 months, as effectively Microsoft are using this time to do a massive beta test - which is one of the reasons why it is free initially.
Okay, he tried with one of yours (Dreamscape) and one made by someone else, and everything looks like it's running correctly. The only thing he reported on Dreamscape was this:
Windowed we have the mouse pointer of Windows along with the mouse system pointer. If that is normal then I got nothing else to report.
I think I've seen that with Windows 7, though. Can't remember for sure because I push the mouse out of the way as I use the keyboard.
But, althoug win 10 is "back" 7, some 7 programs arent work... Now win 7 i can play or feelings at i play one my favorite rpg... althoug i was know begind too cleary...