I am using a modified version of the variable timestep from http://www.java-gaming.org/index.php?topic=24220.0

Whenever I move something (like an enemy), I multiply the speed by delta. The problem is if the game freezes, the enemies teleport off screen and you lose (speed * really high delta). The towers (my game is a tower defense) don’t get any time to fire at them. Is there any way to make it so that it won’t do that or next time should I use a fixed time step or something else entirely instead?