It pains me to give this a game a thumbs-down, it really does, but after 10 hours in, there is just so much fundamentally broken about this game that I can only recommend that people give it a wide berth until the developer finally sorts out the myriad problems with it.
It's a shame, really, because the game's handdrawn graphics are astoundingly beautiful, the soundtrack is wonderful, and its setting is startlingly original. Seriously, how many games do you see set in Aztec-era Mexico?
For the first 10 levels, you tend to be tolerant with the game, because the bugs don't manifest themselves, progression is fairly linear, you expect the somewhat sloppy combat system to improve as you gain skills, and it's just so damn beautiful. The problem is that after that, things start going downhill very quickly.
The game has a hair-tearingly annoying autosave system that saves after each level, and also records quest errors and bugs that cause you to fall into an infinitely deep hole. The combat is atrocious, and eventually devolves into using somersaults to scrape past powerful opponents in a desperate attempt to maintain some kind of combat strategy. Quest texts are misleading and often lead into dead ends, which you often cannot find your way out of without much backtracking, trial and error and - in some cases - a walkthrough.
Compounding these problems is an appallingly bad energy system, which requires you to go hunting for various types of 'energy' to pass certain obstacles. Some - the green 'vital' energy and the white 'divine' energy - are fairly regular occurrences - the others, like the gold 'elemental' energy, force you on an arduous wild goose chase with only a vague idea of how to find said energy.
And that's not to mention some of the possibly worst design decisions ever to be committed to a game - I will simply say "monkey cave" and "gap", which will probably evoke similar traumatic memories in fellow players.