Like most games in the Contra series, Operation C has you controlling a nimble commando who runs through sidescrolling and overhead-view levels, machine-gunning enemy commandos, aliens, tanks, gun turrets, and basically anything that moves. The first few levels are your standard military bases and jungle settings, and the last few use organic "alien" decor inspired by the work of H.R. Giger. According to the manual, the ultimate alien mastermind of Operation C is Black Viper instead of the usual Red Falcon, but it makes no difference. What matters is the meticulous placement of enemies, bullets, and bottomless pits in each level that gives the Contra series its flair, and Operation C crams quite a bit of that into its small package.

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The first two stages of Operation C are rather easy, especially once you become aware of the enemy patterns, but the third level, a jungle stage based on Level 3 of Super C, is where the challenge picks up. There are sections in this level where a gun turrent pops up in front of you while enemy commandos rush in from behind. Without the Homing Gun, this is a difficult thing to deal with. The inclusion of a Homing Gun, much like the Spreader, would seem to negate some of the game's challenge, and indeed it does, but there are actually times where another strategy is more useful. This is the only Contra game I've played in which I purposefully traded a Spreader or Homing Gun for the Flamethrower.

Although much of the stage design is borrowed from Super C, the boss fights are all unique to this game. The Level 3 boss is a two-part tank whose bottom half moves along the floor shooting bullets, while his top half freely floats around, firing lasers and giant plasma bubbles. If you don't destroy some of its pieces quickly, you'll soon find no safe place to go. Another boss is a giant scorpion that spits spiders and fires a diagonal beam that ricochets around the room. Both of these bosses are the kind that will wipe you out the first few times you get to them because without knowing their patterns, you won't know what to do. There are tricks that make them easier, but figuring out those tricks, and then getting to the boss with the right weapon to pull them off, is part of the challenge.

The final level contains the most unique design. There are lightning-quick aliens that leap out of containment tanks and ceiling turrets that fire rapid volleys of diagonal bullets. There is a particularly good sequence in which you ride an elevator up through indestructable laser beams and enemy soliders as more of those test tube aliens burst out at you. Memorization of the pattern is essential to getting past this. The final boss requires a certain rhythm to defeat, although he isn't too tough once you know what to do. Indeed, one of the game's failings may be that if you get accomplished at the earlier stages, it's possible to pass them without dying. Even though you don't earn extra lives very often, you'd probably still have enough upon arriving at the final boss to win by "cheesing" him. In a scene reminiscent of the "false ending" in Mega Man 2, there is a small section past the final boss that ends with you destroying a huge glass tank that contains an alien jellyfish. I have no idea why this was included as it doesn't fight back, except that maybe someone really liked their artwork of an alien jellyfish in a tank and wanted to put it in somewhere.

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If the purpose of Operation C was to be the best Contra game ever, I'd have to say it falls short of that, but since the intention was more to recreate the look, feel, and challenge level of Contra in a portable game, on that level it succeeds. I can easily recommend it to fans of NES Contra and Super C, or those just looking for a decent Game Boy title.