I used to play this one a lot and it remains one of my favourites. The does tend to produce a roughly historical result as the NKs sweep south and the RoK and UN forces are hard put to hold them, then a rear area attack allows the UN to roll forward very quickly but various checks gang up on them to halt the advance short of the Yalu (ie the chinese). Things to note off the top of my head

1. Watch the east coast road carefully in the early game. Too many UN games flounder on a determined NK push here while the RoK is preoccupied with the usual Pusan Perimeter. It should be evident by the middle of the second turn where the NKs are concentrating.

2. Use terrain carefully. Hills and mountains that border roads are very helpful particularly to the communist side later in the game. They restrict UN movement, blunt armour and allow the communists to exploit better mountain movement.

3. Keep a front. Individual units will by cut to shreds as the emeny throws successive units around them and then attacks with the aid of the surrounding units. Three breakdowns in a line are usually better than a single lone division. A cluster of divisions surrounded by open ground can be enveloped and the pocket reduced rapidly by the enemy. Use terrain to cover your flanks if you lack units.

4. Dig! if you get the chance and don't need the unit otherwise use it to dig in. Never waste the use of a unit.

5. The first UN invasion must kill off the NK offensive potential. Usually Inchon but if East coast is a problem hit here, if desperate Wosan (correct name ??)

6. Personal opinion: the UN should get the Chinese in quickly once the RoK border is secured. Push North towards their entry points. Dig in north of Pyongyang and take to brunt of it forward. Then Hit them hard with multipier armoured divisions. If you wipe them here they will be so blunted as to not make it back to Pusan before you can rebuild the divisions and redeploy. The weakened Chinese can then be rolled back towards their borders with time to spare. The key here and perhaps the key problem with the game is the total lack of ability of the Chinese to build new units after their full intervention and if that timetable is triggered at the right time they will be fighting without reinforcements near the end. The rate of NK rebuilds is too slow to save them.

7. Moderate level force committment, medium high air and full mobilisation for naval flexibility and all the National Guard divisions as early as possible. I'd go straight to the levels you want, progressive rises are bad warfare. To win as the UN you need to take a moderate risk of global war. Don't cross the NK border until you can do so in force. send a strong RoK contingent in the first turn over and follow it the next with non-RoK. Never use the nukes, it's a very unsubtle tool!