Not bad! I had a little trouble working out how to interpret the messages about making the upgrades, and exactly where and how I needed to stand to do the upgrades. Also, I had to unplug my joystick to make it playable with the keyboard.
Those are minor technical glitches, though. The game itself was quite good. The art is well done: the retro style is charming, and all the relevant game elements were easy to interpret. Managing the warmth reserve wasn't difficult, really, but it added an element of challenge that made the game much more interesting, AND it really brought home the threat of the cold.
The game was short and simple, and somewhat lacking in replay value. However, I'm not going to count that against the game for two reasons: first, it was made in only 48 hours, and more importantly, the game has everything it needs to convey its message. "A machine should contain no unnecessary parts for the same reason that a drawing should contain no unnecessary lines," and this game contains no unnecessary elements.
I give this game one thumb up for quality work under time pressure and one thumb up for appropriate minimalism. :)