If you've downloaded the exe from -
http://www.wsgf.org/forums/viewtopic.php?f=95&t=30251. Don't do it. This EXE file is for 1.17 version of the game (GOG and others).
The Steam version is 1.18 and it won't run with other EXE (hell, it won't even run, if you try to change a single byte in it). Hence why my script changes both aspect ratio and FOV (while the GOGs version can have aspect ratio edited with hex editor).
Simply install CheatEngine (make sure not to install some bullshit toolbars etc.), download a Cheat Table from:
https://raw.githubusercontent.com/SuiMa ... en/Aqua.ct (right click, save as).
Start a game, ALT-TAB. Start CheatEngine, attach it to Aquanox.exe and load the downloaded CheatTable. Then simply check "Active" field for one of the options (not all). If you use a different aspect ratio than 16:9 - you'll have to change the values in the script (but there is a comment where to do it). Plus the new script allocates floats, instead of bytes that represent it, so it's much easier to edit.