Uurnog is the latest game by Niffalis, the same guy who made Within a Deep Forest and the Knytt games. That said, this is far less ambient exploration like those two games and much more Metroidvania like Knytt Underground was. It's a free game they made for the Humble Store, and it effectively serves as a several hour long demo for the $15 game Uurnog Uurnlimited which is (or at least appears to be) an entirely different game. For absolutely free, this is a great game to put 2 or 3 hours into for an afternoon :D

Though it's kind of a Metroidvania, you don't really get upgrades past initially unlocking the ability to store items. Instead it's more when you unlock certain items and how you unlock different areas to get money from. The actual gameplay is a little bit like Mario 2 (you can pick plants up out of the ground to get items from them and throw them at stuff) but is far more Lyle in Cube Sector as far as the larger gameplay mechanics and artistic aesthetic goes.

Your goal is to find one of each animal around the world and take them back to your safe room. The safe room is where you spawn and respawn and is also where you send items back to because that room never changes while all other areas reset when you die. Slowly finding more keys to unlock doors to new areas is fun, and there's even a small puzzle that unlocks you a kind of second ending, but it took me maybe 2 more whole minutes than beating the normal game, so it's not terribly labor intensive and can easily be done just hopping back in once you complete the animal collection.

Verdict: Recommended. It's not a must-play game by any means, but for a free game it is an excellently designed game that plays great and looks wonderful. It's a good way to spend a sleepy morning if you can't sleep like I had this morning Xp