Is 5.6 million dollars really enough to make a good game?

Of course $5.6m is enough to make a good game. It's important to understand however, that a small indie team making a game has way less overhead than a commercial business doing so - and therefore is going to cost less.

You can't really compare a handful of people making games from their homes with a large corporation operating out of an office building without acknowledging this. Every piece of infrastructure that goes into the working space causes the budgets necessary to justify a project from a business perspective to skyrocket - and that's not even taking into consideration the other needs of the development staff at hand, or how much they're getting paid (which is expected to be higher when they're working for larger corporations - especially when they're located in high cost-of-living areas).

If you've ever wondered why the biggest AAA-budget games that get released year after year are very safe and samey in what they do, it's because they have a fairly reliable return on investment. To put it another way, they keep the lights on for a very, very large series of operations.

That said, Inti Creates is not a particularly large company - about 80 employees - and has only self-published a handful of titles (five, to be exact). Mighty No. 9 is not one of these - as an educated opinion from working in this industry, the root cause of the unfortunate situation in which Mighty No. 9 ended up was likely due primarily to managerial and scheduling issues - that's not to say that development issues couldn't have arisen - though I don't really have doubts as to there having been development issues which took up time and money as well, considering that we're talking about a team that's otherwise experienced neither with the engine at hand (Unreal Engine is, to this day, still a bit of an enigma to the Japanese development scene, with the only high-profile adopters coming in fairly recent history), nor with handling multi-platform development on such a large scale. When you divide resources up this much, with a team not accustomed to it, with technology that's new to them, it should come as no surprise that there will be hiccups along the way - nor should it be surprising that management and scheduling issues would definitely arise from trying to sort this out with other contracts.

As a developer-for-hire, the larger you are, the farther in advance you need your contracts planned out - because of having bills to pay. This likely prevented Inti Creates from being able to put more resources toward the game, and is why it ended up getting shipped the way it did - they have to call it somewhere, and generally-speaking, companies don't have the luxury of being able to simply sit on something until it's good and ready (this is something only a handful of companies can ever really do with AAA game development - this is primarily a Nintendo and Blizzard thing, though we have seen similar things happen with other companies in particularly egregious situations; the post-launch situation of Final Fantasy XIV 1.0 comes to mind). It shifts schedules, pushes contracts, stresses employees and costs a whole lot of money.

(Side note:  I suspect that the ongoing development to create the remaining versions of Mighty No. 9 is why Inti Creates has released so many self-published titles as of late - they probably did adjust scheduling for continued development on the project, but the duties for the staff on the finished platforms concluded, but they need to be kept busy on something - so in lieu of contracts, savings are used to develop and publish small, non-contracted titles, which offer a relatively high turnover rate, being able to be developed to completion quickly.  This is probably also why their most recent ones, Blaster Master Zero and Mighty Gunvolt Burst, are getting a somewhat steady amount of post-launch support in the form of extra playable characters; developing the games finished, final MN9 platform development is ongoing, and these are simply filling up space before their next contract is scheduled to start)

That said, this is likely why Inti Creates is no longer on Bloodstained. Not "because Mighty No. 9!," but rather, because they have contracts and development schedules that couldn't be changed as a result of development timeline shifts that happened for one reason or another. Instead of see a situation happen where the end result becomes more akin to what happened with Mighty No. 9, it makes sense to shift to other developers if more suitable ones are found - especially from a business perspective, if you absolutely want the quality of the product to be paramount - the later into development that a developer shift occurs, the harder it's going to be to make things better.

The other part of why I think this - and I understand this part is far more subjective - is that Inti Creates consistently makes pretty good games otherwise. They're known for the Mega Man Zero series, and Mega Man 9 and 10, and they self-published their own Azure Striker Gunvolt series and the Mighty Gunvolt spin-off crossover series, all of which are actually pretty good, if not great. All of which are 2D games, running on their own proprietary engine, with workflows with which they're familiar - all of these are factors that drive down the time and money investment to make a game happen.