Amazing detailed scenarios and fun gameplay covers up for minor issues (minor) with gameplay mechanics and saving system
First of all the problem with the gameplay mechanics only happens when climbing because you don't climb just up-down or right-left but also diagonally, and sometimes when you are trying to just go up the game doesn't make a good job at detecting your movement so it could go anywhere but up, and as you get used to the controls this is not a problem at all and it happens only (ONLY) sometimes (SOMETIMES) not always. About the saving system, is true that there are not many checkpoints available if you play the game in "Survivor" mode but you get more checkpoints if you play the game in "Normal" mode. I played the game in "Survivor" mode from the start and yes it was a little bit frustrating at the beginning but just like in any other games you'll get better as you keep playing and after a while the difficulty of the game and the checkpoints feel just right.
You have to play smart, find, keep and use your resources only when needed; remember is a "Survivor" game not a happy-killing-fest like other games. The climbing is really fun, there are many places to explore in the game by looking for survivors and helping them, lots of cut-scenes as you complete each objective/parts, a simple story without much mumbo-jumbo and one of the most amazing detailed scenarios Ive seen in a video game, where you also have 360)full control of your camera view behind you. Look at the videos on youtube and you'll see. Also the parts where you have to face/kill your enemies is very challenging and rewarding as you carry out your strategy to take onto 3-5 enemies at the same time with 1 arrow and 1 bullet.
I finished the game in 7 hours but it may take you less (I wasn't too careful too many times); I wish the game was longer or they come up with some extra DLC; I really liked this game, go get it you'll love it.