I also broke through the wall at the speed of about 23. But it only happens really occasionally at then.
Things became out of control after the number reaches 40. With X2 game speed, the character moves like a crazy roach. It feels like...breaking through the barrier before the game defining it.
Maybe there could be some thresholds, or changing some rules from multiplicative stacking to additive. Or just keep it the way it is, as a softcore handy lil game.
Anyway I've noticed this game for weeks. really enjoyed how it becomes better everyday.
Sincerely appreciate, to Amrita.