Low framerate

I recently downloaded the excellent screensaver from breve, but its not running as it should be. When I run the creatures.tz with the normal IDE it runs at a very decent speed, even at full screen. When the screensaver starts though, it goes at a painful 3fps or so.

Is the screensaver more demanding? I would love to know if there was a way to fix this. Maybe have the screensaver run at a lower resolution but stretch to full screen?