Shivelight

Free clicker game. Reach 10 million slaps, then reset your progress. Has a built-in auto clicker. See full review for 'Desktop Pet enjoyer'. ~150+ hours to 100%.

Free MP roguelike. 2 Paid DLC required. Can be cheesed solo. ~30 minutes to 100%.

Free Korean-only VN. Has a console for faster completion. ~15 minutes to 100%.

Wordmaking game. "2500 Levels" DLC required. Change theme to black, then back to white. Start with DLC installed and reach level 350. Refer to extended for a wordlist. ~8+ hours to 100%

Word-making game. Play on English, enable 8 Letters Mode in options, grind 5000 words. Use KB & linked unscrambler for faster grind. All achievements will unlock while grinding. ~7+ hours to 100%.

Desktop widget. Relaunch every 5 minutes until all mums are unlocked. Spend 30 mins with each mum (see achievement icons for hint), and score 10 in volleyball. See guide for Perfect Parry. ~7 hours.

Amazing and fully guided action RPG based on Journey to the West, with some missable achievements. About 2 playthroughs required. ~40-70 hours to 100%, based on skill.

Free and fully guided jetpack shooter with built-in cheat mode. Controller is highly recommended. ~1-2 hours to 100%, based on skill.

Fully guided voyeuristic role-playing puzzle game. ~4-5 hours to 100%.

Fully guided b-movie God of War clone. Two playthroughs required, second on hardcore difficulty. ~9-11 hours to 100%

Free Wipeout-style air racing game. 'Faster' and 'Target Locked' must be grinded out in a single race, more details in linked guide. ~7 hours to 100%.

Free point n click horror. Get all 3 endings, get the first ending in less than 10m, find all mice and coins, find the glitch room, hit the monster with a stone. ~45m to 100%.