Hard and challenging game, but fair and fun.
Your task is simple - get to the exit. The problem is the execution :P You have to use Chameleon's ability to change colors and blend in. You have to hide behind things to avoid detection. You have to distract your enemies to slip past. You have to time things right. Timing IS important. There are collectibles and they are fun to grab - not easy, not impossible, sometimes hard. This is a perfect game for me to hate, but it's not. It was saved by one feature - mid-level checkpoints. Without those I would not enjoy it and started hating the game. Thankfully chekcpoints are present, and even though game is really hard at times, it's still fun.
Graphics is good, so is music and sound. Controls leave a bit to desire - you can't remap things - shame. Speedrunning lovers have a separate speedrun mode. Developer has recenlty released an update containing an easier difficulty and a few more languages.
If you like stealth (yep, that's a stealth game), you have a knack for timing then this game is a good choice.