lucid the slowdown is due to a fix I submitted (SVN revision 153) for a bug where the collision mask did not change when the frame changed with animated sprites. The fix was first in construct 0.99.85.
Here's the tracker:http://sourceforge.net/tracker/?func=detail&aid=2974232&group_id=207820&atid=1003219
My fix was to recalculate the collision mask every time the frame changed. Before, the collision mask would only be recalculated when a sprite's size or rotation changed.
If you uncheck "loop" or set "animation speed" to zero for the animations that are only one frame your fps should go back close to what it was.
did both actually to all sprites, as none of them are animated, and it helped, but still didn't solve the problem