Scratch Inc.

It's internet gambling, but for achievements and not actual money. The gameplay is pretty basic: scratch cards for points, use points for upgrades, keep going through multiple point-type upgrades to eventually reset the game completely and do it all again for a small percentage of an increase. While I usually do enjoy idle games, this one took some serious time mostly because I never played it long enough to keep grinds going in the best places (offline is only 20% of your profits, so you miss a TON not keeping it open), but overall you could beat this game in maybe a day or two if you spent a lot of time managing it and resetting. The grind for 13x13 was by far annoying, but again, that's just the repetitive nature of the game and I chose to bash my mouse against the game for nearly 9 hours to get it. It isn't 'hard', just tedious. I do recommend the game if you want something to play mostly passively, but also a game where you can keep grinding higher and higher (for no apparent reason, though maybe leaderboard claims). It's not bad, it's not amazing. It's just all right.