As most reviews say, this game represents approximately 5/6 hours of gamelay, and has little contents : small map, no ennemies, no loot, nearly no storytelling. But it is good at what it does : fast-paced, skill-based, non-repetitive boss figths. I should also add that the "hard mode" and "true last boss" give it a good replay value. The game is unforgiving but not really punitive. Gameplay mechanics are simple to learn but hard to master. Most boss require analysing the situation and having lightning-fast reflexes... or just being really cunning. If you want short fights that will bring your skills at their limits, this game is perfeclty fine. Some patience is required (I died 524 times on my first, 6-hours run...) but it rarely becomes frustrating since fights rarely last more than 30 seconds. Once you get a hang of it, managing to defeat a boss is a reward of itself. Il you just accept the minimalist nature of the game and use your imagination on the few elements you encounter while visiting the map, it actually has a pretty immersive atmosphere. Its full price is certainly a bit exagerated, but I would recommand getting it on sale without hesitation.
