Unity 48-hour gamejam

In this post I’ll be breaking down some of the approach I took and lessons I learned from working on the design for a GameJam project called Barrel Blast!

You can play it off of itch.io here

This was a project developed over 48 hours using Unity 5 by a team of 5 people. Misti, Thomas, Carson, Rim and myself. I did the gameplay and puzzle design, along with a chunk of the gameplay engineering, but everyone contributed in equal measure to the final product as a whole.


First off, The premise!

You’re aboard a massive freighter that’s adrift on rough seas. Bad dudes are trying to find you in the dark, cavernous hold below-deck. And you’re a… guy who can make certain oil drums explode at will, with a little delay.

It’s a puzzle game that was birthed by the theme “Chain Reaction”. The ship tilts back and forth, making some barrels roll along the floor. You can click them, and after a moment or two, they detonate.

You clear a level by killing all the dudes, which you do by exploding barrels next to them. Since only some of the barrels are clickable, you have to create chain reactions. The image above is the first level where the mechanics are tutorialized.


This is level two. Note the splitting paths. The idea here is to illustrate two things: The position of other elements in the level matter, and a single explosion can lead to more than one chain being triggered.

This level, like the first, is simple in the sense that detonating the barrel in the right spot is all that matters. But, there is another element to consider here, phase.


Rolling barrels actually have two characteristics to their patterns: position and phase; where they are and whether they’re moving left or right. Level 3 introduces this element to the player. The first barrel will be in the correct spot twice during its pattern, but won’t trigger both the cascading chains when the barrel is detonated while rolling to the right.


Level 4 makes the player consider both concepts, but on a longer level, and from a different perspective. It also introduces the idea that walls block explosions. The player’s margin of error for an “optimal” solution on this level is very narrow, but they have additional barrels for a less-than-perfect clear.


With Level 5 we introduce a new type of barrel has a completely different mechanic: it’s steerable, but doesn’t have any power of its own. So, the player has to navigate through the level, using the tilt of the ship to give it them momentum to get where it has to in order to start off the chain.

This gameplay is more tactile and less about puzzle-solving. Note the affordance of the solid-red spotlight, which was introduced in level 3, guiding players to the optimal detonation location.

Levels 6 and 7 are explorations of that same idea with different layouts and more labyrinthine paths.

I enjoyed the experience of making this game as a while. Here are some conclusions I reached.

The Good

  • For a quick project, the team was able to present something quite polished! 48 hours really isn’t that much time.
  • The gameplay quickly becomes intuitive, with the feedback and payoff being quite clear. Players engaged with it rather well, became frustrated at the right points and with the right intensity — more “grrr, gonna get it right this time!” instead of “meh, too hard. Laters.”
  • The combination of elements leads to a surprisingly wide design space. There are a lot more possibilities for new entities that detonate and can be detonated.

The Bad

  • In order to allow the player to consider more than one rolling barrel, they need to be able to always see it in relation to all the others. There is only so much depth a level.
  • Furthermore, the only real effect of additional rolling barrels is to narrow down the “optimal solution” window without really increasing complexity. This leads to the wrong type of frustration — the one that comes from mechanics rather than puzzle-solving.
  • Phase and position are questions answered quickly. The depth of the complexity of rolling barrels on their own is limited.
  • Didn’t have time to explore the whole design space.

Whut I durn learned

  • Experimenting leads to unexpected results. The steerable barrel, for example, was a bit of an accident.
  • Design aids, like a display that shows a designer the radius of a barrel’s explosion speeds up design and iteration considerably. (Thanks Carson!)
  • Good versioning is absolutely crucial for good collaboration.

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