My favorite App Store games this week have something in common: they're all a little bit odd. Aliens, apocalyptic romances, and uncanny valleys abound in our weekly roundup of iOS games. The other quality these bizarre games happen to share? They're free! So you may as well explore their weirding ways.

1. Fallout Shelter

The free iOS spin-off of Bethesda's detailed-oriented role-playing franchise taps in to the hyper-organized apocalypse survivor in us all. This version takes out all the aimless wandering and pelt-skinning of the original Fallout games, focusing instead on the analytical and administrative difficulties of running a radiation-free underground bunker. That doesn't sound too weird, except for the part where any time you put a guy and a gal in a "Living Quarters" room, they'll be making babies within minutes. Who knew the apocalypse had the power to turn everybody so straight —and so desperate? There must be something in the water refineries.

2. Ronaldo & Hugo: Superstar Skaters

I don't know what Cristiano Ronaldo is famous for, but based on this game, it could be his ability to turn his head around like an owl, or perhaps the eerie smile that remains plastered to his face even when he's about to skate head-first into a steam engine. Ronaldo rides over roads, grinds on candy cane-striped rails, dodges colorful obstacles and avoids paparazzi in this endless runner that coasts gleefully into the uncanny valley and performs a few cool tricks on its way there. The central skating game feels smooth and slick, and the bizarre cast of characters charmed me even though I had absolutely no clue who they were or why anything was happening. I've got to dock a few mental points for the constant ads, but other than that, I dug it.

3. Mean Girls: The Game

I doubt Tina Fey expected her clever screenplay to result in a mobile tower defense game released over a decade later, but someone must have signed off on this inexplicable experience. The in-game dialogue reads like an unlicensed fan-fiction, and all of the characters from the original film have been rendered as bizarrely drawn caricatures. Cady, Damian, Janis, and the rest join forces to protect their high school cafeteria from cliquey newcomers, but they have to rely on high school stereotypes to do it. Early on, a Santa Claus pops up and reminds you that the Glen Coco meme exists. Aaron drops by from time to time to quiz you about what day it is. This game is not "good" according to any reasonable definition, but it's so earnestly unaware of its own bizarre behavior that it manages unintentional hilarity.

4. DooFLY

I wanted to write DooFLY off for its thoroughly unfair coin-saving system, but flying the blue balloon feels so good that I can't help but keep pressing replay. The game's design begs for a Flappy Bird comparison, but unlike the notorious FB, DooFLY is not so difficult that it can't be enjoyed. Each power-up heightens your speed, but as soon as the effects wear off, you'll get a little shield time to slow you down and let you adjust your timing for avoiding planks once more. When you inevitably hit a plank and plummet downwards, the game asks you to use a certain number of coins to "save" yourself, but the number of coins required changes at seeming random, and the "save" screen never tells you how many you have remaining. So, it's a little weird... but I can't deny it's compelling.

5. Shuttle Shuffle: Aliens Panic

Shuttle Shuffle is a few months old, but it did receive a massive update this week; the new version includes a "summer graphical style," because it's "summertime on all the planets." What does that mean? And why does the game's music sound like it belongs in a Western shoot-em-up instead of an alien-themed puzzle game? Couldn't tell you, but hey, that's why it's on my "strange picks" list this week. Don't be fooled by those cute little alien eyeballs, either; this game is hard as heck. If you want easier levels, try some in the fan-made level editor section of the game — or make your own with the user-friendly design tools.

6. Your favorites?

Have you played any unusual free games this week? Or perhaps you'd like to persuade me to play more typical fare. Share your picks in the comments!