That's odd, not a problem I've seen before. It's written using Monogame, I'm not sure which version of DX that targets, a quick search doesn't reveal much. There is no DX switch. I've just compiled an OpenGL version for Windows if you'd like to try it. The link is http://www.bitglint.co.uk/temp/mmgl.zip
Kudos, it is indeed a rendering issue, the GL build runs perfectly. (Looking closesly, I realized the DX build on my machine not only flickers but also stutters)
I saw there's a dll named SharpDX.Direct3D11 so I assumed it's DX11, but it's just a guess, I'm not familiar with it myself....
I played a bit, pretty fun, and pretty hard! (even with Stamperlot!) I can live with not having a map whenever I want but the constant hp drain really makes me want to start up a certain "engine"... then I scroll down and see someone beating the game with all 4 characters with a hand drawn map... seems like I've been spoiled by modern game design... (though I think I'll still use "the engine" eventually...)
Thanks for the GL build again!
Oh yeh of course, it'll be DirectX 11, I'd forgotten about the SharpDX files. Yeh it's a hard game to start with, but becoming familiar with the map makes things easier. There's also a hints and tip page at www.bitglint.co.uk/MelkhiorsMansion if you're getting stumped. Anyway, glad you've got it running ok now, I'll add that GL build to the download list. Have fun! :o)