Coming from a Nintendo Life interview with Casual Bit Games' Chris Obristch...
NL: Will Battle Princess Madelyn make use of any of the console's key features, such as HD Rumble and same-screen multiplayer with two Joy-Cons, or is it going to be the same version across all formats?
CO: There is no multiplayer planned for this game, we had learned from our past title Insanity's Blade that it dramatically alters the game from the original vision. We will be doing HD Rumble, but essentially it'll be the same version across all formats.
NL: Could you see yourself making a game exclusively for the Switch which made use of its unique features?
CO: We don't have any ideas that would be exclusive to the Switch at the moment, but who knows what the future holds! As an owner of a Switch, I'm definitely interested in pursuing the possibilities after we get a few more game ideas off our back-burner. That doesn't mean we aren't open to Switch-specific features in our future games too, of course!
NL: Last time we spoke to you it was about Insanity's Blade, which was due to be released on the Wii U. What happened with that?
CO: Although we never met the Wii U stretch goal, we still tried to do a Wii U port after the Kickstarter. Initially we had the game completed in the Construct 2 game engine - which, based on the advertising when we bought it, was supposed to export to the Wii U with HTML5 and WebGL. However, when we got the dev kit it ran at about 10fps and bugged out terribly. There was nothing we could do about it, as we had no control over the engine. We had a dev under contract to do a Unity port but that didn't pan out well so we had to cancel the contract. It's important to note though that it was not the Wii U that was the issue here though, and thanks to the flexibility of the Unity engine we are looking forward to Battle Princess Madelyn's release on Wii U as well as Switch!