playing the 400-one campaign defense against thedark ones,the game keeps on "freezing" while using all possible buffs.

while it started around level 300 its gets worse and worse with increasing difficulty (aka enemies present on stage/ buffs in use). While the game still seems to register most of the input (hotkeys pressed,mouse clicks, upgrades purchased), the game needs A LOT OF TIME to process the wanted action. For example an activated ability will be triggered 30s until up to a minute later, stopping clicking the game still displays clicks, the "stage radar" stops keeping up ....

while at the end stage with the "surge of magic" buff running out, it is key to have all abilities usable, which at the moment they are not. Abilites are triggered while the party is already wiped, effectively makingthem useless AND wasting time until next try (cooldown).
Also crusaders cant be upgraded in a timely fashion as the "clicking upgrades" is no longer registered.

FYI: I finished them all with no memory issues at all

The longer you play any flash games without a cold boot, the worse it will be