There remain compelling opportunities for 'paid for' games in the mobile space despite the continued rise of F2P games, according to Nathan Vella Co-Founder & President of Capy, the creator of premium games like Critter Crunch and Sword & Sworcery.

Speaking at GDC 2013, Vella argued that, while an estimated 66% of revenue generated in the App Store in 2013 was from free-to-play games, around $2 billion came from paid games.

The argument that "paid apps are dead" is disingenuous, Vella said. "There is still a huge amount of opportunity in paid games - so long as you find the right game for the business model."

Vella argued that there are lots of niche genres with fans who are willing to pay for games up front when they appear. "Many players don't even know they want a game in a particular niche till one arrives," he said citing iOS titles The Room and Year Walk as games that have found vast success over the past few months despite being idiosyncratic titles that don't easily fit within an established genre.

As part of our Road to the IGF series, sister site Gamasutra is speaking to each of the finalists in the 2013 Independent Games Festival to find out the story behind the games.

Today we speak to Tobias Neukom, whose iPad game LiquidSketch is nominated for the Techncial Excellence award thanks to its impressive liquid physics.

Sleepovers are really just elaborate, animated Tetris puzzles, suggests Anna Anthropy's and Leon Arnott's free game TRIAD for Windows and Mac. Players must learn the sleeping habits of three humans and one cat to make sure they all fit comfortably on the bed without bumping into each other. Once the terti-humans are in place, players can click off the lamp and watch how they toss and turn. I found that when I took too long to make some moves, I wore out Liz Ryerson's music that otherwise fit the late-night mood.

Here's to hoping TRIAD becomes a live-action, physical game in future indie events, maybe with more tertri-humans. Each player also must communicate and then role-play their sleeping habits until they arrive at a solution. Or something.

Polytron Corporation's puzzle platformer FEZ is finally making the trek from Xbox 360 to Steam for Windows on May 1. FEZ features a wonderful rotating mechanic that allows players to explore a 3D world from four, 2D perspectives. The main character searches for the shattered pieces of the Hexahedron cube, which gave him the ability to see in the new perspectives.

Coinciding with this announcement, FEZ co-creator Phil Fish is answering questions IAmA on reddit now. So far, Fish has confirmed a Mac port is coming, but its date is TBA.

Cave Story developer Studio Pixel's next game is not Rockfish, but Gero Blaster, an action platformer heading to iPhone in Spring 2013. The footage surfaced in the above collage of Japanese indie games shown at the first BitSummit event held in Japan today.

Nintendo Life found a tweet from Nicalis' Tyrone Rodriguez showing off Gero Blaster running on a Nintendo 3DS XL (without the big virtual buttons, too), suggesting the game will see other ports. There was no mention of a PC release, yet.

Braid developer Jonathan Blow will bring The Witness to the PlayStation 4, he announced at Sony's press event today. Specifically, PlayStation 4 will be the only console The Witness will appear on during the game's "release window," Blow said.

Blow also revealed the game's first trailer at the PlayStation 4 event. The trailer is under heavy stress, but it is embedded after the jump.

Yoshio Ishii's exploratory puzzle/guess game Which? asks you to identify 20 different items based on certain qualities. You'll poke and prod the circles to figure out which is soft, light, heavy, new, sticky, and other observations which are not normally discovered with the mouse. Be sure to play it with the sound on, as some clues are aural in nature.

Nekogames' latest will only take a few minutes of your time, but its playful discovery should keep you interested until the end!

[source: bontegames]

A small team of Italian developers are working on a riot simulator (RIOT) based on worldwide events. Leonard Menchiari heads the Indiegogo project that will target iOS and Android devices first, with eventually PC and Mac ports following.

"The main purpose of this project is to create a game that will get people to be interactive with two opposing forces during clashes between rioters and police while showing the moral aspects and viewpoints of both sides," the campaign states.

Adding to the heavy-hitting games this week is Bogazici University student Talha Kaya's narrative platformer Ode to Pixel Days. The player is able to go back in time, thereby pixelizing himself to the point where he looks appealing to the cheerleader that dismissed him earlier. Or, so Hans tries.

Kaya writes in, "The game is played in a castle that represents the world created by Hans' mind. The game's artistic goal is to put the players in Hans' mind, to make them play through his emotional experiences, hopes and dreams. The core experience of the game is the feelings a boy goes through when he gets into puberty: loneliness, sadness, low self-esteem, the desire to change things about you and everything around you."

Crafted following the style and sensibilities of a ZX Spectrum game Father Jonah Saves the Day is a simple, short, colourful and delightful arcade adventure. Uhm, play it, will you? It's well designed, incredibly easy to pick-up and unashamedly fun.