iO Review

By Brandon Fusco,
Analog puzzle games are not a new thing, running the gamut from traditional carnival games to the likes of Angry Birds and Trials Fusion. iO is the latest of this lineage, combining the problem solving requirements of traditional puzzles with a need for skillful manipulation of your avatar. Will iO's size changing mechanics be enough to make a splash in the genre, or will it shrink off into the distance?

iO ReviewDeceptively simple.

Changing the size of the wheel shaped avatar in iO is the game's main unique feature that sets it apart from what could have otherwise appeared as a Trials clone. While the left stick controls the rotation of the wheel, either clockwise or counterclockwise, the right stick allows the wheel to either grow or shrink, in turn changing the physics of the sphere itself. For instance, a larger wheel is capable of reaching a higher top speed, but a smaller one may be capable of using the additional space afforded its size to build up to a higher actual speed over a given distance.

As a simple spatial puzzle game, iO is particularly well designed. The simplicity of the colored lines that make up each stage lends an air of intention. No part of the game is designed to look fascinating at the expense of a clean gameplay experience. Each curve, hazard, and moving platform is clearly placed with intention, whether it be as an obstacle, path, or both.

iO ReviewEach plus is a rotating set of landings and launch points.

Mastering the ability to shrink and grow is tricky, partially because there's very little reference for the player. While the wheel can only shrink or grow to a certain minimum or maximum size, figuring out the exact size of the wheel beyond that is almost impossible since there's no fixed point of reference to relate to. As the player shrinks or grows, the camera zooms in or out, providing a different perspective of the play area.

In theory this allows better relative precision, but in practice it becomes very difficult to discern relative location or speed so you can experiment from attempt to attempt. For example, the wheel carries horizontal momentum in the air better when smaller, but this also zooms the camera so far in that it's impossible to see landmarks. The result is that trying not to overshoot a target by increasing in size has more to do with lucky guess work than any masterful manipulation of size. With each attempt, a minute difference in approach can change the trajectory, so increasing size at the apex may work in one instance and not at another despite not being able to pinpoint the difference between the launches.

iO ReviewWhere am I? I'm lost again!

When things click, manipulating the wheel around the environment so that it whips around corners, shoots through the air, and lands on the exit is engrossing. There is usually only a single particularly difficult obstacle in any given level, except for the challenge levels in the late game. Frequently, levels will put together several mechanical elements into that obstacle to great effect. Often times, it's the smallest realization that leads to success, such as how rolling in reverse when a catapult launches the wheel will give it just enough extra momentum to get across a gap. Figuring these things out and mastering the elements of the physics engine are always rewarding, if sometimes frustrating because of how big an impact a small difference can make.

Some environmental mechanics are still not entirely clear or consistently effective, such as jets of air that push the wheel upward, or portals that move it across the map. Trying to find the exact boundary of where the air will catch the wheel can be tricky, and it's not easy to figure out at what point the wheel will become too heavy to be buoyed by the air. Similarly obscure are the portals, which fail to indicate where they will let the wheel out once it goes through. Oddly enough, it's even possible to go about 75% of the way through a portal, stop, reverse direction, and actually go through the back of that same portal (an incredible feat in a 2D game). The result is often that the wheel somehow accidentally comes out of the back side of your intended destination and falls off the map.

PortalsIf you approach the portal on the right from the bottom without enough speed, the wheel may not pass fully through, then fall into the back side of the portal.

Unfortunately, consistency between levels tends to be a problem. Frequently, there will be a particularly difficult level that requires judicious precision, which is then followed up by a level that is almost as simple as moving in a single direction all the way to the goal. Rather than being a nice gust to propel you forward, it ends up feeling more like iO has improperly prepared you for that particularly hard level while also disrupting any ramping difficulty.

There's also a skill that isn't brought up in the tutorial and isn't introduced until about 20% through the main game. This particular skill requires the wheel to slowly increase in size to allow it to climb up vertical walls. It's one of the most difficult skills to master, yet no explanation is offered as to its nuances. It could become impossible to finish quite a few levels scattered throughout the game until the skill clicks on its own.

iO ReviewDidn't learn that skill from 70 levels ago? Then this is one of many concept levels that you could have finished easily, but currently can't.

The end result of all of this is a janky mess of progression where certain levels will be skipped because there's a strange difficulty spike or because you haven't mastered a skill through a careful series of levels designed for the purpose. Rather than a feeling of growth earned through playing increasingly more difficult levels, it instead feels like being really bad at a game and cherry picking the levels you can play.

If the arrangement of levels could be mixed up, the experience would move from a mere fun experience with clever puzzle design to a consistently enthralling and rewarding series of challenges. Once iO's various skills are mastered, the varied layouts, one-off levels such as mazes, and neat combinations of mechanics combine for some truly mind bending enjoyment. While it only occasionally hits this sweet spot, the masterful level design can temporarily elicit the kind of addictive mindset of other more consistent games.

iO ReviewIf you're a hair off, you're done for. If you can't finish even one level like this, three trophies are off the table.

The trophies are, unfortunately, much more consistent. Of iO's 13 trophies, eight of them revolve around either getting a certain total quantity of medals, achieved through beating certain completion times on levels, or by attaining every silver or gold medal. That leaves only five trophies, four of which require the wheel to shrink or grow as many as 10,000 times. The last trophy simply requires each level be played at least once. With no real variety, the list will likely prove to be a slog, and if there is a single level out of the 225 that ship with the game that you can't figure out, that instantly locks you out of nearly a quarter of the list.


Within iO resides something genuinely fun. The mechanics and level design are anywhere from solid to fantastic, and from simple to devilishly clever. An unfortunate couple of basic problems make the experience a bit of a mess, however. A game like this requires an intense marrying of both spatial problem solving skills and precision control, but iO has a tendency to obfuscate the information necessary for a smooth experience. Whether it be a camera zoomed too far in, a lack of reference for wheel size, spikes in difficulty from level to level, or an absence of a proper explanation for a high level skill, the inability to properly communicate with the player can quickly and regularly derail what is an otherwise solid and even occasionally addicting game.
6 / 10
  • Interesting mechanics
  • Precision gameplay
  • Clever levels
  • Poor communication of vital information
  • Sometimes too precise
  • Bad stage ordering
The reviewer spent seven hours completing the main set of 150 levels, as well as a couple of the insanely difficult challenge levels. He collected 5 of the 13 available trophies. A PlayStation 4 version of the game was provided by the publisher for the purposes of this review.
Brandon Fusco
Written by Brandon Fusco
Brandon is an Editor and TGN's Host with the Most. The most what? The most opinions, the most understanding wife, and the most *funny cat videos. Previously Host of the Trophy Talk Podcast. (*Not Verified)
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