CAVE "Hardest Video Game Boss Ever" Interactive, Co., Ltd.
Especially when they are struggling so badly to get onto non-smartphones outside of Japan.
These are some of what I've bought, all working on US 360 without modchip, and all playable thousands if not millions of times over, despite each being no longer than 30 MINUTES. Now THAT'S game design.
European version, PAL/US regions
Japanese version, all regions
Japanese version, all regions
Europeans also have this to look forward to next year. (No idea how USA will get it, if at all.)
Also various indie bundles, including all the Humble ones.