In this stream, the game ran at a much higher speed than usual.

He didn't have this issue in earlier streams. It may have something to do with his monitor's refresh rate, and vsync being disabled by external programs. See this thread on the Steam forums:

https://steamcommunity.com/app/201420/discussions/0/846958724736278143/

The bug may have been fixed by now. But Marstead is using the DRM-free version from the Humble Store (tokitori2_windows_1389720725.zip). This is an older version, which doesn't have the ancient frog hint text popups.

I'm reminded of Far Cry 2 speedruns, which also exploits a bug that makes the game run much faster. (Not that I'm interested in such a category.)

Woah! that would kinda be fun to try out, just casually :D