I finished two of the three games:
Kero Blaster
fun, but especially the latter bosses are challenging (at least for me), therefore I also only got one achievement yet.

There Came an Echo
Innovative, though the voice recognition doesn't work for everything / at all times, story okay, setting good and nice credits. Got 75 % achievements, maybe I'll go for 100 %, but had to work on Kero Blaster first.

I won't start the third game now, since I'm leaving for a business trip in two hours, so it was already very close. Thanks for the event, LastM! :-)

These were my games: https://www.steamgifts.com/discussion/2hocj/level-10-celebration-cuphead-ga-rule-change-play-2-instead-3-games-to-participate/search?page=2#GNJOLhm

I finished "Reflection of Mine", but still have a lot of achievements to do, bc I didn't get perfect scores and played on normal difficulty, not hard. The game was a lot more difficult then I thought it would be...

I was aiming to beat all three games that were selected for me but I think I'll just manage 2 of them.

Else Heart Break() requires a different mindset for me to enjoy it. I'm just too tired at the moment... maybe next time :)

I finished two out of three!
In the spirit of the giveaway, I still will get to Stardew Valley. In the spirit of I work a full time job and have other adult responsibilities, I may not get to it soon.
Portal 2: Quite a bit longer and more challenging than the original. There's some good background info if you pay attention, and some moderately difficult puzzles regardless. Beware: Mood Dust is TOXIC!
More ending scene screenshots available on my Steam profile.
7 Wonders: I misunderstood what kind of game this was. I hate it. It's a cheap bejeweled-esque type game that has almost 0 originality. The level design seems more like creators wanted to make things look cool more than functional as a game (there were a couple parts where it was IMPOSSIBLE to "match" tiles, and you had to get lucky and get a warp power-up to drop there to even clear it). Terrible game that I wouldn't wish on my enemies.

Done : http://steamcommunity.com/id/yobokkie/stats/appid/72000/achievements and http://steamcommunity.com/id/yobokkie/stats/appid/284870/achievements
I have crookz installed and intend to play it, but it's a bit longer to beat

Finished two out of three, might not have time to squeeze in the third before event ends (put too much time on ESO last month :P). Will have to get back to LiS:BtS when episode 3 is out >_<

Original comment
The Walking Dead (missing achievements for DLC)
Life is Strange: Before the Storm (missing achievements for unreleased episode)

Link to original post
Got it done at the last minute! I beat Never Alone and Broforce! Both good games in very different ways.
Never Alone is a story based platformer retelling a Native Alaskan folktale. It also comes with "cultural insights" that are unlocked as the game is played and put together it probably makes a feature length documentary about the story, the people's history, and how the game was made.
Broforce is a parody on USA action movies. Characters are hyper-masculine musclebound heroes from pop culture. The end-game screenshot I provided gives a decent idea of the type of humor in the game as the player is addressed by the President saying "After all you have done, I have but one request. High Five me Bro!"

Game Complete Achievements:
Never Alone
Broforce

Oh and if I needed screenshots:
Never Alone
Broforce

Edited for formatting

Beaten two out of three games from the list:

• Danmaku Unlimited 2 - fnished the game in both modes - Classic and Burst
• Little Racers STREET - the campaign is never ending but I got the "Best of the best" achievement (Get to 1st place in the ranking) which is kind of the main goal of the campaign.

I hope I'm not too late! I just finished two of my games

Furi and Gods Will Be Watching

I quite enjoyed both of them, especially Furi! I'll definitely replay that one, it's challenging but really fun to play and it's absolutely beautiful (the soundtrack is really dope as well)

I finished first part of Jotun
I played some Warhammer® 40,000: Dawn of War® - Game of the Year Edition (6h)
and played some Goat Simulator (6h)
It was fun but i got tired of Warhammer (cool game but not my type) and Goat Simulator (throw up machine)

Finished the main story of transistor but I liked it a lot so I'll go for 100% later http://steamcommunity.com/id/aeonian_chacma/stats/appid/237930/achievements
and made some kitties presidents
http://steamcommunity.com/id/aeonian_chacma/stats/appid/474980/achievements

Chosen games : https://www.steamgifts.com/discussion/2hocj/level-10-celebration-cuphead-ga-rule-change-play-2-instead-3-games-to-participate/search?page=4#eP392LF. I finished Wolfenstein and The Walking Dead, tried out Lakeview Cabin but I was lost at what I'm supposed to do.

Wolfenstein: http://steamcommunity.com/id/bored_one27/stats/350080/?tab=achievements. FPS isn't my favourite gerne but I had a blast playing this one, just got myself The New Order and looking forward to playing it.

The Walking Dead: http://steamcommunity.com/id/bored_one27/stats/TheWalkingDead/?tab=achievements. I understand why this game is popular, got me nearly crying so many times.

Almost there, I finished Earthlock, and hopefully I will be able to finish Owlboy tomorrow

I am sad to say this is the first challenge me kinda thingy that I failed :(
Flame in the Flood: I really like the game but it is just too hard for me. 7 hours in (out of the 9,5 on HLTB) and I can not get past checkpoint 3/10 in the campain :(
Momodora: Reverie Under the Moonlight: This game frustrates me too much and the last thing I wanna do after a long day at work is to play a frustrating game >.<
Nulcear Throne: too late to start it now.

https://www.steamgifts.com/go/comment/HX5yewS

That was close but I made it, I finished Earthlock & Owlboy