The most important thing when writing a game is, in my mind, getting an absolute bare-bones playable entity as soon as possible. Make it so there is no engine. When I start a roguelike the first build is just a character moving on a map, and the sooner the better. Don't get bogged down in wondering if you have anticipated every possible connection between objects that you'll need. Put pieces of engine onto your game rather than pieces of a game onto your engine.
In terms of maintaining oop principles, you should just do whatever works for you. As far as I'm concerned, "Public:" is part of the opening brace of a class definition. I write things very strict and very sloppy at different times depending on what type of mood I'm in, and it doesn't seem to make a real difference to me. I could see that type of worrying being important if you are coding a game with someone, since you want the code style to be the same across the board, but otherwise don't worry about it. You'll end up writing cleaner code automatically (and if you get upset about an old bit of code you can do a small rewrite of that section, faster because you'll be more experienced).
Really, to anyone else who has problems dealing with large blocks of code, my advice is to just keep making more programs and games. Each time you make one, you make the next faster, cleaner, simpler.