Deep Sea Valentine is a little different from other dating sims, because the route isn't determined by "affection points" or a similar stat mechanic. You're free to say whatever you want to the other characters, and it won't affect your chances of going on a date with them. This means it can be difficult to figure out what does affect the ending, though. That's what this guide is for!

I recommend you only read this guide after you already tried a few things yourself. It contains a few spoilers and is meant as a last resort to prevent you from growing frustrated with the game.

There are exactly three points in the game where your choice will affect the route you get:

• return the sawfish to Moka / forget to do so
  (this decision is finalized when you visit Tae's house in the purple forest)
  
• use chocolate on crab / keep it
  
• exit the cave right away / turn back
  (only relevant if sawfish wasn't returned on time)

This should already give you everything you need to get all the endings on your own. For the fastest 100% run, just save the game right after freeing Tae, before making your choice for the crab, and when you're given the opportunity to turn back in the cave.

The Shortcuts feature added in Version 2.0 should save you even more time!
You'll find more details about it further below.

Here's what you need to do to get the route you want:

• return the sawfish to Moka
  
• use chocolate on the crab

• don't return the sawfish
  
• keep the chocolate
  
• turn back in the cave

• return the sawfish to Moka
  
• keep the chocolate

• don't return the sawfish
  
• use chocolate on the crab
  
• exit the cave right away

• don't return the sawfish
  
• keep the chocolate
  
• exit the cave right away

Triche is both the hardest and easiest to romance. Aside from the "bad" ending, you could technically always end up dating her. Details in the next section.

Below are all the correct answers that will allow you to go on a date with your girl of choice:

...unemployed. / ...sense of humor. / I do.
...an e-girl. / ...making sweets. / I am caring.
...a waitress. / ...I'm cute. / I won't!
...a chiropractor. / ...I do.
...a photographer. / ...rescued Feli. / ...I can.
If you get all answers wrong, you will go on a date with Triche instead. (Just choose the opposite answers of the ones indicated above.)

You can also get a "bad" ending where you can't romance anyone (including Triche) by doing the following:

• don't return the sawfish
  
• use chocolate on the crab
  
• turn back in the cave

The shortcuts button is a new feature from Version 2.0. It let's you jump right to an ending if you've read the relevant scenes from the common route.

The "relevant scenes from the common route" involve the following factors:

• Bringing back the sawfish
  
• Not bringing back the sawfish
  
• Giving away the chocolate
  
• Not giving away the chocolate

If you do all of these things across your playthroughs, then you will also unlock all shortcuts.

The most efficient method only requires two full playthroughs of the game to get all seven endings:

• After rescuing Tae from the seaweed, save the game
  
• Do one run where you bring back the sawfish and give away the chocolates, and reach an ending*
  
• Do one run where you keep the sawfish and keep the chocolates, and reach an ending*

*The order or exact combination doesn't matter here, the important part is that both runs have the opposite choices.