there is a techie way to beat this problem, but the easier way is to run zzt through tucan's old "zzfont" utility, available
here. unzip the contents into the directory you keep zzt in, open the bat file and zzt will run through a font that simulates the "proper" ms-dos font. it's not that sophisticated but it works
oh, and it needs to be run in fullscreen to work, so alt+enter is your friend (or better yet, alter the program settings to "run in fullscreen")