You can use any and all prefabs as long as you have the rights to them. If unity’s prefabs have open use rights on them then it is perfectly fine, so long as you announce before hand that you are going to be using it.

Oh and as far as tips go, here’s a couple

1) Spend your first hour or so planning. You won’t regret it.

2) Stick to the plan.

3) Don’t include features that will waste time and aren’t important. The most important thing is getting a game out, not having eye-candy graphics and gigantic levels with intricate design and easter eggs

4) 48 ours is a long time. I managed to get my first entry in ( which due to C++ didn’t work ) in under 20 hours and it is a pretty well polished game.

5) Sleep is super important. Family is super important. Don’t make your game take up all your priorities or you will “run out of gas” so to speak.

6) Stay cool, and do what you know how to do. I’m good with platform engines and isometric engines, so I should stick to those. Don’t experiment if it’s going to endanger the success of your game.

7) Getting out a game is the most important part of ludum dare. Even if it’s not the best, even if it doesn’t look the coolest, the fact you got a game out is on it’s own an achievement.

8) Use your weaknesses. I am terrible at game art, so I make this a strength by using minimalistic graphics, which look very good without having much artistic depth.

Good luck, sir. See you on the front lines.

Well, Unity’s prefabs (mainly the first person controller) come with unity. Would that count as open use rights as anyone with unity can use them?

All right, let’s try to clear things up before the disinformation spreads:

Thanks to all that commented!

I think I’ve got it all figured out now.