Woha they must have gotten lucky or made some good breakthroughs with development or testing in my mind since I saw their estimate release blog post about DLsite made me think then that it could be an Summer 2024 release so for me, they've churned through over maybe a year's worth of work or at the very least 6 months of work possibly since then.
As a result this does make me start to get a bit concerned though about the size of the game as keeping in mind the Demo was released about 3 months ago it was complete up till the second boss, adds the question to me of how many bosses are planned and if it's going to match Mission Mermaiden's length and content at least. Since I recall seeing them showing what could be the full teleport/fast travel map in one of their dev videos and in the Demo we got access to just under half those spots with two at minimum not having anything to do or going on in them due to story stuff I believe. Additionally for Mission Mermaiden they had like 7 bosses right (technically 2 as one was a two stage fight)? 3 of which were in the final area while two was in each area so if the map is the same then I worry about fitting all those bosses in without cutting them out. So I hope, hope, hope, that the map has been expanded upon since that dev video and this does end up even bigger than Mission Mermaiden but I feel it would be wrong to not remain sceptical and cautious since there's too many games that have seemed promising that flop massively even though some had games made before them which were wonderful works.
PS As I felt like the hypnochair and tentacle wall traps never got a chance to shine in Mission Mermaiden as a result of them being purely in the last like 2-3 levels, I don't know if that's just me though?
(MCswagger's mod helps a ton with getting the hypnochair more noticed since it also removed each unique chair having to be visited and forced you to them) I think so due to maybe attempting to cram them in slightly at the last bit of development without enough time to fully test that last area zone out.