It looks unusual for a DSLR because it lacks the prominent viewfinder hump that normally contains the pentaprism or pentamirror that bends and flips the light from the mirror into the eyepiece.
Instead, the E-300 uses a thing called a Porro finder, where the mirror swings sideways rather than up and down...
Alas, if you're used to the big, bright viewfinder image offered by the pentaprism on a full-frame pro body, the multi-mirror Porro finder on the Four Thirds E-300 is a little cramped and dim.
.