Misery, I can't duplicate the thing with it not switching between day and night when it changes turns. Are you still seeing that? Is anyone else seeing that?
I was thinking abou enemy boss behavior/spell patterns but splices is a good concern too now that you mention it. I hope we get some multilevel arenas. And some really interesting boss behaviors, boss battles in metroidvania games tend to be epic and what I remember the most in them.
They're just never going to be a centerpiece of this game, I'm afraid. I've made things more varied, but I've focused on making things more in line with the rest of the game just on hyperdrive. Thinking about games like Prince of Persia: Sands of Time, that's a game that had a lot of great core mechanics, and what they did for the final level was pit you against more of those core mechanics in a really interesting way.
Or thinking about recent Mario games, Super Mario 3D Land had a final boss fight where Bowser is chasing you and things are crumbling and you're running for your life. It's a lot more interesting than the Bowser boss fights in Mario Galaxy, for instance, which strayed into completely different mechanics from the rest of the game and were shallow and repetitive for it. Same with Mario 64, really.
Metroid games are kind of a different beast, and the boss fights are built in as a really core mechanic. That requires a really intense amount of AI and design for a specific boss fight, however, and I think we can all agree that playing the same 6ish boss fights from Super Metroid over and over again wouldn't be terribly compelling. They are epic in the context of that game because each only happens once, period.
But with a procedural game like we have here, especially one that encourages serial playthroughs because of the strategic component, that's just not something that fits with the design -- having hugely involved battles on the level of Super Metroid would either lead to huge amounts of repetition of really specific stuff (ugh), or it would lead to an exponential increase in development costs due to us having to spend ridiculous amounts of more time to create dozens or hundreds of boss battles where the entire Super Metroid staff at Nintendo just had six.
All in all, what that really means is that the the boss fights need to overall stay out of the way; they are now a lot less frequent than they were in prior versions, for one thing. And for another, they are mixing the general game mechanics (rooms with other enemies in them) up with the bosses themselves to create a combinatorial effect. It helps bring some of the feel of the tactics of the combat of the rest of the game to the boss fights, while not making them too overwrought or lengthy.
Based on my playtesting I think that this is enormously more successful than the past boss fights were, but we'll see where there is room for improvement as more people get their hands on it.
Goodness, that was quite an explanation -- I think this will have to go in my release notes!