I think the alternate tick system will still work on a 120Hz monitor - at least in my example, it still uses dt on alternate ticks, which means it is moving in half-as-big steps at 60 Hz instead of normal size steps at 30 Hz. If you force dt to be constant, you are making a game design choice that breaks this, and the game will run double-speed on a 120Hz monitor.
As for varying the logic update rate, I can't see it working for a general purpose engine like Construct 2. There are two options:
So I don't see that either option is really any better. C2 has always done one logic step per display frame, and I think that makes most intuitive sense anyway: any less and sometimes there is nothing new to draw, any more and you burn CPU time simulating stuff you'll never see. And C2's approach has worked well for a very wide variety of games.
Develop games in your browser. Powerful, performant & highly capable.
Ashley you're right. You're always right. Thanks again, and sorry to have taken up so much space to figure out this stuff.