Not overtly realistic yet not much arcade fun either...
The problem with P.H.M. Pegasus is that it was produced following some very uncertain design philosophy. Because it ain't a hardcore simulation, nor is it a lightheaded, fun seeking game with boats. It's something of an in-between, and that in-between doesn't do it much justice. It's got a few scenarios, in which you play from within the...cockpit of your ship, doing nothing but sailing the perfectly blue sea, and hunting for other ships and sometimes planes. But, and here the realism part undercuts the game, you never get quite enough enemies on screen at any one time. And when you do see them, you don't have a lot of time to shoot them down until they destroy you. The fun part that gets undercut is mostly represented by the sketchy way the controls work, and by that I mean that you need very little in order to move your ship around, even if, had it respected the rules of physics, some of the maneuvers it can do would have been in the realm of the impossible. Thus, I'd rather urge you to download Strike Fleet, a much better simulation, and one that offer you better in all the main, important aspects: simulation, content, a bit of strategy and a more enjoyable game.