I've been playing quite a bit of this over the last week - I'm on the second statue and just finished the underground mission (I had to use the Youtube walk through to find that entrance - it's not that obvious) Also, there are 3 crates to pick up - not just the first one surrounded by the crabs in the large room. I thought it was a glitch at first as it seems like you only need 1 crate from the guild notes. You have to drop into the tunnels (again, not totally obvious because you can't clearly see they are holes at first - they appear more as black pits. Just keep thrusting down (or up) and you'll 'eventually' make it to the tunnels below or above. The underground/subway section is actually huge - there are 2 more crates underground, both on train platforms in about the same place.
https://www.youtube.com/watch?v=cPD9NvK2fK4&t=135s (it's around the 1m 30s mark)
The same channel has video guides for every aspect of the game if you're in difficulty.
It's such an amazing thing to be able to play this game and actually understand what's happening - I'm sure I've said it before - but a massive thanks for making this possible. Definitely a dream come true
The crazy thing is that I have 3 dreamcast consoles but they're either a) packed away or b) messed up with a bad GDEmu clone that I just wouldn't trust to actually hold the data (and keep it). So, purely by chance, I ended up with one of these cheap devices in early December:
https://www.youtube.com/watch?v=B4Sv_hbYJ70&t=442s
I wasn't expecting much for the Dreamcast side of things but, believe it or not, it's been running Blue Submarine No. 6 perfectly so far. Okay, not 100% perfect - the only graphical glitch I've spotted so far is during the 'loading' screen. I was expecting a lot worse, certainly not playable.. but it is completely playable. - Note: there are a ton of games it doesn't play - I'd say it's about 50/50 just messing around with it. I do wonder how powerful these cheap Chinese boxes are going to be in a year or two from now? We're well beyond the NES/SNES clones that I remember.
There's a basic Dreamcast compatibility list here
https://www.reddit.com/r/arcadebox/comm ... andard_43/