It seems to be running fine here. Construct provides tools for you to check performance and investigate why things are slow if you run the debugger and look at the profile tabs. That's the first place to go.
To be clear, the version I linked was using the C2 runtime.
When I load that program and choose the C2 runtime, it takes 12.89 seconds for my text message to scroll up the screen and the next scene to fade in. If I then choose the C3 runtime, the same sequence takes 56.25 seconds. So I'm clearly doing *something* wrong.
Okay, I just checked the debugger with both the C2 runtime and the C3 runtime. I'm not an expert but everything *seems* okay, except I did notice a big difference in CPU usage. During the text scroll:
C2 RUNTIME: 60 fps and 92% CPU
C3 RUNTIME: 26 fps and 1.8% CPU