Horse Racing is a browser take on the track: a field of horses, a set of odds, a race that lasts under a minute, and a result you have no control over once the gates open. You choose which horse to back and how much, and then it's out of your hands — which is precisely the appeal.
The odds mean something: the favourite wins more often than the long shot, but the long shot pays for the times it does. Everything is played with in-game credits and there is no real money involved anywhere.
No. Everything is played with in-game credits — there is no deposit, no payout and no gambling of real money.
They express how likely a horse is to win: short odds mean a likely winner and a small payout, long odds an unlikely one and a big payout. Over many races they roughly balance out.
Yes — tap to pick and race. It runs in the browser with nothing to install.