Code-Name: Iceman

The Good
The idea of mixing a basically pure adventure game with arcade sequences is nothing new. The addition of a simulator is already something novel and interesting. I have to admit it, while I also state that I always disliked simulator games and that steering the submarine in "Codename: Iceman" did nothing to change my mind - I didn't like these sequences, but I appreciate the idea. As for the types of puzzles, there is also lots of variety - everything from flirting with a girl (who soon turns out to be an agent too), through repairing machines, decoding messages (it's hard to figure out exactly how it works and the system involves copy protection, but after some time it actually got quite fun) to finding and freeing the hostage.
I liked the graphics, but I generally like good-quality EGA graphics, sometimes even better than duller VGA graphics and definitely much more than 95% of 3D graphics. A modest palette of juicy colors with clever use of shading works fine in different settings from a tropical island to sub machinery.

The Bad
However, despite these advantages the game also has two big flaws: a very high difficulty level and crazily excessive use of copy protection measures. In "The Colonel's Bequest" it was enough to find the correct fingerprint in the manual and while this wasn't integrated into gameplay at all, at least you didn't have to worry about copy protection afterwards. In "Codename: Iceman" copy protection is employed several times: first you have to check out the first aid procedure and basically retype it in the game (luckily it's a SCI game which pauses when you type), then use the manual to look up passwords for decoding messages (three times!) and check out how to turn on some devices such as the sonar. Plus, it's better to familiarize oneself with the rules of the "Boss Dice" game in order to make sense of it.
After about 1/3 of the game has passed, terribly hard sequences pretty much bang you on the head one after another. Boss Dice is a game of luck and you can only restore it twice (at least there is another, albeit more complicated, solution to the puzzles which involve the objects won: a bottle of rum and a magnetic device). The two battles are also very hard and luck-based. Later you have to follow another ship to get into the Mediterranean safely - getting and staying under her is hard, but first signalling her correctly is enough of a pain. In the coded message you are told to signal the ship with a single "ping", but when using the sonar you get two kinds of little sounds: a "click" when turning the sonar on and off and a small "beep" later. How am I supposed to know beforehand that yes, I have to turn the sonar on and immediately off, without waiting for the "beep"? It's easy to think it's the "ping" you have to signal... At the end there is another action sequence that you luckily can bypass: escape from the terrorists. What I found really annoying is that the game reacted very slowly to everything I pressed - timing it right is next to impossible. You have to speed up to be able to escape, but the van actually reacts only when you already ahould be slowing down before another curve...
The simulator sequences may actually be harder for modern players than they were when the game was made - at least on laptops, which don't have a separate numeric keypad. It involved constantly turning Num Lock on and off - "on" to speed up (numeric "+"), "off" to be able to type things like "close hatch" or "depth attained", "on" again to adjust speed...
At the end yet another detail - saying "I didn't like it" would be nitpicking, I'd rather describe it as a funny lack of realism. Some cabins on the sub look like hotel rooms. Well, I've never been aboard a submarine, but from what I've read it seems pretty clear submarines don't look like this. The pressure they have to withstand is so immense they must have as little surface as possible. Often they don't even have beds for all the crew - one shift is sleeping while the other works. Again - I wouldn't say it's really a disadvantage - the rooms look nice enough (even though the "hotel"-like cabins are actually rather boring, some other screens like the machine room or weapon room are much better), but it's a bit curious in a game so much acclaimed for its realism.

The Bottom Line
Anyway, I would say the game is worth trying out. Despite its flaws it remains interesting. But be prepared for a hard and frustrating game. Myself - I'm happy to keep a screenshot collection in my emulator, but I doubt if I'll ever play the whole game again.