Trench
You're gonna have a hard time with google search placement. Trench is such a common word. I'd also go for something that denotes "deep ocean" or "under the sea" more clearly. Trench just reminds me of war.
Seriously though, who is on Google searching for games? People go to Steam, GOG or their favorite review site.
You have a
very, very narrow concept of who plays games. I'm not on Steam, I don't know what GOG is (should I google it? but nobody googles game stuff...), and don't check review sites.
Why would someone want to google a game name? Because they heard about it but don't know where to find it, or didn't catch the full name. Because they're writing an article about it or similar games and need to fact-check, or want to read reviews of it, or any other conceivable reason.
Telling someone they don't need to think about Google SEO (search engine optimization) is like telling them they don't need to promote their game once it's released. Literally every branding agency in the world factors this into naming new products and services. (I work for a branding agency.)
Naming things is hard. But for games I think there are 3 rules
1. Be relevant to your gameplay (ie: don't call your driving game "cookery")
2. Don't be dull (ie: Don't call your game "Flight Game")
3. Be easy to say without sounding like a dork (ie: Would you be happy discussing your game with your friends? Or would you feel silly? THATS how your customers will feel.)
Well...
1. Don't name your game after a gameplay element – Super Mario Bros, not Jump Man.
2. Being direct can pay off: SimCity, Civilization, Minecraft, Street Fighter, Mortal Kombat.
3. A cool name for one person is silly to another. Most fantasy game titles set off dork alarms for me.
My tips for developing a relevant and memorable name can be found
here.