Yea I ran into the same problem of nothing happening when I hit the Play button too. I actually downloaded an earlier version of this game before it was released on steam, which was a patch released on 14.12.2015 or Dec 14, 2015. The filename from IGG was called "Unveil14.12.2015"
I found out that if you just copy the "steam_api.dll" file into the game folder from that older version then you'll be able to play the game! I've packed the file into a RAR archive and uploaded to MEGA. So I'm not uploading a game, just that one file from an older version of the game that gets the game working and its only 753kb big.

1. Download here: https://mega.nz/#!BwFjVYwa!vmoQVPNDdgvJHLPCs2yhFo2biasLe_WmmR9R0JP_7Vw
2. Extract and move file into your Unveil game folder and replace the steam_api.dll file there.
3. Launch the game from either "Unveil.exe" or "LAUNCHER.exe". Either one will work.
4. Play :)

Nothing happens when I hit play.

Doesn't work. In the main menu I hit Play and nothing happens.

it doesn't work dudes. that's the second game that actually doesn't work and causes problems.

It is a Keyboard-Only Game, thats why mouse is not working.

it would be nice that this actually worked .. at this moment I am believing those stars are fake rating ... When I download and extract, it opens you can click and enter all the menus BUT PLAY -_- seriously if there is more to this then tell it cause other wise this fails bad ..

why doesnt this work... click play and does nothing -_-