All depends on what you're developing. I'd argue that engines like Unreal are deeply unsuited to quickfire events like jams. Maybe it'll improve in UE4, but the iteration time is just too slow as UE3 is geared towards large scale production, and flexibility comes first.
Not sure if Unity is any better, not used it enough.
Outside of engines, managed languages like Java and C# have some very powerful features for speeding up development, like being able to change code while it's running. But not being games engines, they require you go hunt down the tools you need and build lots from scratch.
Regardless of what you choose, you need to know it well. To do well in a jam you need to have workflows established for assets, code, etc. That is what is most important. Learn something, learn it well.
If you plan on a 3D game I'd highly suggest Unity over all other engines. Due to it's component based nature it's a lot easier to prototype with. However I'd suggest staying away from 3D for game jams if you're on your own, make 2D games instead.
For 2D engines Game Maker, Construct 2, Stencyl, and Game Salad are all worth looking into. The less coding you have to do to get your game up and running the better.
Unity took home the super-happy-friendly piece of software for the last 2 years running, and it's probably the easiest, quickest piece of software to get into.
Before you go to the game jam though, I'd heavily recommend grabbing and familiarizing yourself with the editor (should be fast) and grabbing and testing the following packages.
Unity First Person Prefab.
Hard Surface Shaders Free (instant awesome shaders)
Strumpy Shader Editor (if you're not using 4.0 and you like ode-based shader editing)
And the unity bootcamp demo (for basic scripting)
A day with those and you're ready to start cracking in Unity.
It's also incredibly forgiving. My coding isn't great, but even someone with a few weeks of Python can hack something together.
We used Unity for the Global Game Jam this year and it got us over the line with pretty inexperienced coders.
I'd probably go 2d for the next one given that its quicker and easier to hammer things out and that's pretty much your primary concern when you've got a mere 48 hours to play with.
Well Construct 2, Stencyl, and MMF2 will allow you to put your game up online instead of as a download so you'll likely get more people playing and reviewing it that way. Game Maker can do it too if you shell out the $ for Game Maker Studio.
I'd say just try them all then pick the one that you like best. They're not that hard to get started with.
Replies
Not sure if Unity is any better, not used it enough.
Outside of engines, managed languages like Java and C# have some very powerful features for speeding up development, like being able to change code while it's running. But not being games engines, they require you go hunt down the tools you need and build lots from scratch.
Regardless of what you choose, you need to know it well. To do well in a jam you need to have workflows established for assets, code, etc. That is what is most important. Learn something, learn it well.
For 2D engines Game Maker, Construct 2, Stencyl, and Game Salad are all worth looking into. The less coding you have to do to get your game up and running the better.
http://www.yoyogames.com/gamemaker/windows (Mac)
http://www.scirra.com/construct2
http://www.stencyl.com/
http://gamesalad.com/
If you are an experienced coder take a look a L
Before you go to the game jam though, I'd heavily recommend grabbing and familiarizing yourself with the editor (should be fast) and grabbing and testing the following packages.
Unity First Person Prefab.
Hard Surface Shaders Free (instant awesome shaders)
Strumpy Shader Editor (if you're not using 4.0 and you like ode-based shader editing)
And the unity bootcamp demo (for basic scripting)
A day with those and you're ready to start cracking in Unity.
It's also incredibly forgiving. My coding isn't great, but even someone with a few weeks of Python can hack something together.
I'd probably go 2d for the next one given that its quicker and easier to hammer things out and that's pretty much your primary concern when you've got a mere 48 hours to play with.
Which do people suggest?
I'd say just try them all then pick the one that you like best. They're not that hard to get started with.