**NOTE** If you have met these requirements already on either the XBLA or GWFL Lunar Lander you get the following three achievements for 60 as soon as you purchase the game.
There are three medal types: Score (750 points), Survival (5:00 minutes), and Play Time (50:00 Minutes).
You get 50 Points for a proper, soft landing. Then of course there are a few multipliers scattered about to increase that. So a 5x landing would net 250 points. So I would attempt 5x landings as often as possible to obtain 750 points for a gold medal. Keep in mind you can float most of the way down to keep your fuel consumption low, and that it may be beneficial to shoot for a 2,3, or 4x multiplier if it is considerably closer.
If you want a visual example, just view the leaderboard section from the main menu. From here, you can view the replays of top players on the Global WP7 leaderboard to get an idea on how to score big.
This simply means you must survive in a single play session for a set amount of time or longer. The gold medal is obtained after 5 Mins. To survive a long period of time, just work the throttle to float as long as possible, score does not matter. You'll likely obtain this naturally though anyways on your gold medal score run.
You must play a cumulative 50 minutes for the gold medal. May happen naturally as you work towards other achievements, otherwise float as long as possible to run up the cumulative clock.