In this game you play a character who has just died, and you need to control every aspect of his body manually (moving individual legs to walk, blinking, breathing). The gameplay is very linear, there is a story that unfolds and tasks you need to accomplish one by one.
The fun is the awkward controls, like Surgeon Simulator, I Am Bread, and Octodad. Although Manual Samuel isn't as good as those other titles, it is still OK and fun (especially the first half of the game)... and then you start encountering some enemies you have to fight which is less fun, but manageable, until the final boss level. Ugh. I hate boss levels at the best of times, and this game just makes it even worse! Annoying, frustrating, tedious, not a single smidgen of fun to be had. I was fighting the final boss for probably close to 30 minutes of my 2-hour playtime for this game, barely making any progress, and I thought: "Do I want to put myself through this just to finish the game?" Answer: "No, no I do not." And so I quit.
It's too bad that a horrible boss battle ruins an otherwise OK game, but unfortunately for that reason I cannot recommend it at all. Maybe if you really enjoy boss battles AND games with awkward controls then you might enjoy it, but everyone else should steer clear!