I'll bet you're expecting me to fill this review with Cerius/serious jokes, but I won't, Ceriously (whoops!). Instead I'll tell you about the plot (rustle of cassette inlay)... oh, there isn't one. That puts a stop to any witty first paragraph, I suppose. (Get on with it. Ed)
It seems that you must drive your Avenger V4 tank through loads of screens of Exolonesque landscape, blowing things up, shooting things down and generally revelling in all out wanton destruction. Most of the familiar features from Exolon are here - teleporters, flying aliens, missile launchers and add-on armour. There are a few new bits - you must collect codes to complete each level and solve four-letter anagrams (brain blending. I'm sure!). And you can go back to screens you've already completed, something you do quite a lot, as useful items can only be reached by quite torturous routes.
The main downer in Cerius is the size of the playing area. Someone got into the record books by writing the Lord's prayer three hundred times on a postage stamp or something, and it looks like Cerius has got a good chance of beating that record. I'm sure that there's some good technical reason for programming it this way but it does detract from the playability a little.
Apart from the size of the screen, the graphics are neat and the sprites move smoothly with only the lightest attribute clash. The keys are responsive and all the sound and other effects are first class. What's really lacking is any long term addictiveness. You see, Cerius suffers from the same problems as its big brother Exolon; sure, the game is hard to beat, but the action soon becomes repetitive and boring - the screens all require similar strategies to complete and the alien attack styles never change.
At a penny under two quid, Cerius is worth considering, but only if you like, or haven't already got, Exolon.