What would you like unlocked from the start? Why?

Before entering this thread, I thought you meant what in-game abilities should be unlocked from the start. Like: displaying enemy names, displaying damage numbers, double jump, moon jump, wall jump, backdash, etc.

Cheat codes, local co-op, speedrun and async

Why -

Cheat codes for difficulty, if the game is to have them, kind of have the point of them defeated if they can't be used in your main run of the game. If you only have access to them when you can already NG+, there isn't much of a use for them. I don't like the idea of cheat codes in general for games unless they're hard and kind of "need" them, which Iga's games almost never do, but thankfully in this case it seems that there will be more "silly" ones or perhaps ones that might not be silly, but alter the experience somehow in a neat way, not really affecting the difficulty. For instance, how we can hit all four shoulder buttons in the demo to switch spoken language can be considered one of these. I imagine the majority of them will be like that, not so much "infinite health" or whatever.

Local co-op: same as above, for this to be truly enjoyed in the context of what it's meant for, two people enjoying the game casually together, it should be available out of the gate, at least within the mode itself that it's allowed. If a friend has the game and knows it has local, but there's the caveat of "oh gotta wait until I beat the game before we can play this", one or both of them would likely lose interest before that happens. If however this is only for a local version of "online challenge" or something like that, which is unlocked later, then I think it's fine to have that unlocked later. We just don't know much of anything about how this will work yet, if the local co-cop involves the main game at all. My earliest assumption was that the second player would participate by controlling something like a familiar in the main game, which amusingly enough is what Timespinner ending up doing in their game (check it out btw, very Igavania).

Speedrun - this should be allowed both for convenience sake for runners and their events, as well as how it doesn't spoil anything particularly, actually the opposite since it presumably removes all story content and extra presentation that would take up time. Instead of being on the main menu, this could be a toggle for file select/creation.

Asynchronous multiplayer - this is something we all expect is built into the main game itself rather than any sort of separate mode.

Don't you mean Butt Butt's Butt Mode?

I agree with purifyweirdshard on all accounts. Those four are the ones I picked as well.

For me I'd go with Cheat Codes mainly because I think it would be fun to accidentally discover them while playing the game your first time through (you'd be fiddling around on the main screen/or a loading screen and it finishes loading only for you to find Miriam & all the enemies now have big heads or find that all the candles now exclusively drop Mac & Cheese instead of mana pedals, etc.) and Online Challenge mode mainly because I think it would add a nice little wrinkle by giving players the option right out of the gate to either play the story/main mode or go online and fight a total stranger. Now I was originally going to toss in Classic mode as well but after thinking about it I think that this would be one of the modes that should remain locked until the player has beaten the game or met certain criteria instead of being unlocked from the word go.

This one's funny for me. I don't NEED anything unlocked, as I see Bloodstained as a single-player game, so I'll gladly take my time to crawl through it and enjoy whatever "unlocks" come along the way as enhancements to the base experience. Everything I've seen so far (excepting a few rough graphical edges and whatnot) looks absolutely fantastic, so I really don't think I'll be hurting for anything additional.

All that being said, if Co-op IS an actual thing, that needs to be included out the gates. The reason I say this is because my wife would probably join me if we can dive into the game together from the onset. She's not going to want to wait three weeks until I've played through a substantial amount of content on my own to join me at a later time. We both enjoy the initial thrill of discovery. It's like watching a much-anticipated movie together for the first time, versus one person having seen it already and just taking a friend along for a re-view. Not the same experience.