What game is that?
This. Do want.
It's an Angband variant, except it's so heavily modified from Angband that it's barely recognizable.
What's really got me hooked on it is how elegant the design is in absolutely every aspect. The interface, controls, and all of the game mechanics are really easy to understand and fairly simple, but still offer a statisfying amount of complexity that forces you into interesting choices. The balance inherent in these mechanics is damn near flawless.
Example: In general, heavy weapons have more damage dice. Str adds +1 to every die. So a warhammer rolls a 4d2, unless you have 4 str and then it's rolling 4d6 for damage. High Str characters want to use heavy weapons. On the other hand, the critical hit threshold is directly tied to the weight of your weapon. If your weapon weighs 10 lbs, you get an extra damage die for every +17 you succeed over the difficulty to hit. If your weapon weighs 1 lb (but only does 1d4 base damage), you get an extra damage die for every +8 over the difficulty. So you can go the other direction and have a very nimble character who uses small, low damage weapons but gets very large criticals. Note: Some creatures are resistant or immune to criticals. Other creatures have really high armor that makes it damn near impossible to harm them without criticals. You really have to know your character's limits and just avoid situations you're not built to handle.
The guys also seem to know their Tolkien. It really feels like infiltrating Angband. The devs even say that it's possible to win the game without ever striking at an enemy with a pure stealth build, just like Beren and Luthien.