Connect 4 - Four in a row game

Connect Four (also known as Connect 4, Four Up, Plot Four, Find Four, Captain's Mistress, Four in a Row, Drop Four, and Gravitrips) is a classic strategy board game played with 2 players. Each player chooses a color from red and yellow chips and drop a chip into a unfilled column of choice in turn.
The objective of the game is to be the first to form a horizontal, vertical, or diagonal line of four of one's own chips.
You can challenge your friend in a 2 player mode or you can play against the bot. The game offers 5 levels of difficulties (Very-Easy, Easy, Medium, Hard and Very-Hard). Hence, it is suitable to a newbie as well as an expert player.
Use strategy to connect four of your chips in a line while blocking your opponent from doing the same.
The game works offline too. It can be your great time-pass while traveling or waiting.
A great brain exercise for all age groups.
It has similar concept as in tic tac toe and gomoku (five in a row) but different strategy.