If you have an older Mac running Mojave or High Sierra, you might need to contact reFX support directly. They sometimes provide legacy links to paying customers who own Nexus 2, but for a demo of v2, they will likely just tell you to try Nexus 4 instead.
If you are on an M1/M2/M3 Mac (Apple Silicon) running macOS Ventura or Sonoma, Nexus 2 is dead. It will not load in Logic Pro, Ableton, or FL Studio. You need Nexus 4 or 5. Refx Nexus 2 Demo Dmg
Every 5 minutes, the volume will briefly fade out and back in. No Saving: If you have an older Mac running Mojave