Having moaned a lot about the game, the graphics aren't terrible, and it does contain some genuinely novel touches.
Re-loading your weapon, for instance, is necessary when you've emptied a magazine. Some of the sound effects are also excellent, such as the zing of the cases being ejected out of the side of your gun during battle.
However, on the whole I wasn't particularly impressed. A few novel touches aside, Radiaki is nothing special, and the control system really wound me up.
It's not really bad by any means, and a novice with no Doom experience might enjoy it - although I doubt if there are many PC owners who haven't sampled the delights of the game yet.