[PC] Free - Big Fish Legend (was ~$9.60 AUD; permanently free since 22 January 2019) - Steam

This is a game targeted at kids. It can be classified as a cute casual side-scrolling platformer game incorporating a few easy puzzle elements.
Full price until 22 January 2019 was about $9.60 AUD - then it became permanently free and at that price it is definitely a deal.

From the website:

One summer day the old friend Rat tells the kitten legend about Big Fish.
The kitten has a desire to get the fish and starts its journey.

The legend tells that there is one big fish in the world that can be caught by only the most strongest and bravest one.
The kitten has a desire to get the fish and starts its journey.
The kitten passes 3 islands on its way: tropical, snowy and desert island.
On every island the kitten needs to gather a particular quantity of artifacts (fire, water, feather).
These artifacts open the way for other islands. The unexpected outcome waits for the kitten in the end.

Game features:

• 3 worlds
• 13 various monsters + 4 bosses, with every boss player should use a special strategy to vanquish them
• adventures on earth, in the water and in air
• more than 60 picturesque levels
• comix scriptline insertions between the levels
• intricate plot with unexpected ending
• climbing the walls becomes easy and funny now
• solving logical and physical puzzles
• extraterrestrial abnormalities will be in the way
• only in this game kitten can fly using Kamikaze-Birds
• The kitten-rogue has a main role in the game
• there are 8 trophies that can give the kitten special abilities

Enjoy!