Igloo Trampoline (AGAW #3) Postmortem

Overview

Igloo Trampoline is my third game created as part of the A Game A Week Challenge. After last week's card game, I knew I wanted to focus on programming for this week's game. That said, that was all I knew at the start of the week. I went throughout Monday without any real idea of what I'd create. I expressed my concern to my girlfriend and asked her for the first word that came to mind. She immediately (and weirdly confidently) replied with "igloo." After discussing the odd nature of her word (we live in Florida), I asked for another word and was rewarded with "trampoline." I had my mission, and I set out to design a game around this unlikely word pair.

The design took a few days to fully coalesce, but once it did I found myself envisioning a game in which you build an igloo out of ice blocks using a trampoline as your only tool. I thought this idea was pretty funny and could make for a unique game, so I started sketching out how I thought it would play out. I knew you'd have to bounce the blocks of ice with the trampoline, so they'd have to be launched at you. I imagined the polar bear from Ice Climber lobbing ice blocks at the player, forcing them to move around to intercept them and bounce them towards their target.

That vision remained relatively unchanged from start to finish. While details varied (the Ice Climbers bear became the Super Mario 64 snowman), the core gameplay remained constant throughout the week. Implementation-wise, everything was pretty straightforward, with the bounce physics being the clear highlight in terms of both complexity and fun to solve. Speaking of which, this game as a whole felt like a puzzle to solve, and I had an absolute blast tinkering with it over the course of the week.

Mechanics The main mechanic in Igloo Trampoline is the ice bouncing and the involved physics. When I had a pretty good grasp on the core gameplay, I honed in on the idea of using the mouse to control the bounce trajectory. The first thought was to have the mouse position determine the force vector applied to the object, but I thought that would be too difficult since it wouldn't be indicative of the actual path traveled by the ice (due to gravity). So then I figured the mouse position would control the actual path traveled. The ice would bounce in a parabolic arc and reach the apex at the mouse position. This meant that I was looking for the force I needed to apply to the ice block in order to get it to travel through the desired point. With that in mind, I set out to actually make it work.

A couple of Google searches quickly revealed that no one had a solution for something like this. I decided it couldn't be that hard and cracked open the old notebook to math it out.

The vertical component of the force was pretty easy to figure out, but the horizontal component proved more tenacious. As always, I was pleasantly surprised when the quadratic equation proved correct. It feels like black magic every time, but here we are.

It wasn't too involved, just some manipulation of the basic projectile motion equations from introductory physics. While I was not a fan of physics class, I must admit that I had quite a bit of fun trying to figure out what force would yield the desired trajectory. I love puzzle solving, and this is an example of everything I love about programming and game development.

Also, this isn't entirely accurate because things break if the mouse position is under the player position. I didn't have time to really delve into it so I settled for making Ey always positive (at least 0.01) and capping the horizontal force at 15 (as it skyrockets when Ey is small).

What went right? The game feels good to play from the perspective of the player physics and controls. When compared to Arcane Combat, the player character looks and feels a lot better to move around. The ice bouncing was also a hit among playtesters, I heard from a few people that they just enjoyed bouncing the ice around. This was great to hear, as I spent a lot of time making sure that worked well and felt intuitive.

I think the design was a success. I designed the game top-down to fit the words igloo and trampoline, and that's what the game is all about. For a description of top-down design, check out this article from one of my favorite game designers, Mark Rosewater: https://magic.wizards.com/en/articles/archive/making-magic/top-down-and-goal-2003-06-09. Speaking of Mark Rosewater, he has spoken at length about the idea of how restrictions breed creativity. That concept is clearly at play with Igloo Trampoline, as I certainly wouldn't have come up with anything remotely resembling this game without the restriction of having to fit it to a random word pair.

Another win with this game was its presentation. After being disappointed by Arcane Combat's visual presentation, I took pains to ensure that Igloo Trampoline looked good. I wanted it to catch players' eyes and look like a functional and completed product. To that end, I used outside assets (to say that my artistic abilities are lacking would be a terrible understatement) to improve the visual quality. I got to play around with spritesheets and edited the player character's sprite to make him hold a little trampoline. I'm quite happy with how the game looks. It's easy to understand what's going on and it looks charming. I can't ask for much more!

What went wrong?

I've learned that my tolerance for difficulty is a lot higher than that of many other people. While I thought that correctly placing the ice blocks to construct the structures was difficult, others found it frustratingly so and many people gave up without correctly placing a single block. That was definitely disappointing to hear, but good feedback. Every game I've made has seen people complain about the difficulty, so I definitely need to take that feedback into account. I don't want to remove challenge from my games, because I personally love challenging games and I know many others do as well. However, there should be options that allow players with a lower difficulty tolerance to enjoy the game as well. I think this was the main takeaway from this game, and it's something that I plan on focusing a lot more on in the future.

Next steps?

If I revisit Igloo Trampoline, I'd like to make the trajectory of the ice blocks visible until you successfully place the first ice block. This would let players play around with the physics and better understand their goal while reducing frustrations. Once the first block is placed, the guide path would disappear and could be re-toggled. This would let players select their own difficulty; it's there if you want it but not needed if you prefer a challenge.

An example of the trajectory that would show for the first block (and would be toggleable afterwards)

I'd also like to add more levels. It's not too difficult to do so; all that's needed is to record the positions of the ice blocks that make up a given structure and tweak the UI. I could pretty comfortably knock out more levels in a pretty limited time.

Wrap Up

All in all, I'm pretty happy with how Igloo Trampoline came out. I accomplished the two main goals I had but failed again in providing a fun & appropriately difficult experience for my players. I will endeavor to pay greater attention to difficulty in the future to provide a more enjoyable experience for my players. Thanks for reading! -Lloyd