There are various puzzles in the app store that provide a realistic replication of physical reality and use gravity, momentum or friction to make puzzles (as discussed in an earlier post). Another physical phenomenon that lends itself to design interesting puzzles is reflection. Three puzzle games in the app store (try to) realistically represent reflection, and make nice puzzles in that surrounding.
Enigmo (shown to the left here) was one of the first games in the app store. It was even announced at an Apple presentation before the app store went live, so it drew a great amount of attention when the app store opened in the summer of 2008. The game is made by PangeaSoft, a longstanding Mac-game software developer, and the terrific success of their iPhone games made them switch completely to developing only for this platform. Enigmo is a desktop game from 2003 (still available from PangeaSoft), and there is in the meantime also a sequel Enigmo 2. The iPhone game is a direct port of the 2003 game, which shows how powerful the iPhone is. It is like a computer from five years ago!
The objective of Enigmo is to guide droplets of various substances to their individual goal, using all kind of tools to guide the droplets around obstacles. The droplets will glide along sliders, bump off switches, and be reflected by drum-like trampolines. The whole environment is a physics emulation, and the path of every drop is determined individually—they will also interact with each other. The position of all the object is continuous, so most of the time you will be fine-tuning the precise position of the tools to obtain the desired effect. The results are gorgeous ‘machines’ of droplets jumping around, and hopefully finding their way to their goal.
Enigmo shows fantastically what this touchscreen is capable of. Zooming and panning, positioning object, and fine-tuning their direction is all completely natural. A really well-made puzzle game. The downside is that the levels get a bit boring after a while. The main difficulty becomes even more precise fine-tuning of the tool-position, and not any new conceptual problems. However, the hours spent before you get bored are well-spend and worth the price.
Laze (shown at the top of this post, and to the right) is in some way alike to Enigmo. However, instead of a constant stream of droplets, in this game there is a laser-beam that has to be guided to a goal. Differently from Enigmo you don’t have tools to reflect the beam. Instead, the screen is full of objects that block your path. There are three kinds of objects: (colored) mirrors, (black) light-absorbers and (transparent) prisms. The objective is to position the laser in such a way that the beam reaches the goal, using the mirrors and the prisms to reflect the beam, and evading the light-absorbers.
The physics of the reflection are really nicely made, and the effect of slightly changing the position of the laser will often radically change the path of the beam. The prisms in particular lead to all kind of funny effects. Sometimes the solution only uses very few mirrors (as in the level shown in the screenshots), but in other levels the beam has to make strange paths before reaching the goal. There are numerous levels (the app says 500+100 different ones), and there is free choice of difficult, so you can play at whatever difficulty you find most interesting. Some trial and error is often necessary to find the solution, but it really pays off to think a bit about the solution, and not just try out all possible positions. A really enjoyable game.
One strange aspect of Laze is that gradient of difficulty ranges from 40 to 100. I was a bit confused at first by this, and I still wonder why this gradient cannot be simply normalized to a range between 0 and 100. Probably there are even simpler levels possible with a difficulty below 40, but when they are not used, they should also not be implied. From another perspective, it might be interesting to add such really simple levels, because they might be useful to explain and play with the physics of reflection in schools!
The final puzzle in this set is Diamond Hunter (shown to the left). You have to guide a diamond from a drop point (top left in the screenshot) to a goal (mid bottom), using trampolines and walls as tools to guide the diamond. In spirit, this game is identical to Enigmo, but the execution leaves much to be desired, The controls are awkward, and the physics are very simplistic (and often not very realistic). I suggest you better spend your time on the previous two games, and leave this one for those who didn’t read this post.
[Update 28 March 2009] A clone of Diamond Hunter became available today: Squished. It might very well be the same developers that are behind this title, because the company Alcomi that originally made Diamond Hunter seems to be disbanding and cooperating with other developers (see for example the story about Dr. Brain and Space Trap/Open Doors). Hopefully they have updated the physics engine.