The high difficulty and high playability of Mega Man series of video games are very popular with players all over the world. But personally, I only like few versions such like Mega Man X5, any 3D versions are never considered. If you are obsessed with Mega Man style of small games for PC, don't miss 30XX.

ShadowFlare is a fantasy-themed adventure/action role-playing game very similar to Diablo 2, developed by Denyusha and published by Emurasoft from Japan in 2001. We can regard it as a Japanese style of Diablo coming with its own characteristics and supporting both singleplayer offline game mode and multiplayer (up to 4 players) online game mode, although Japanese game developers are really good at creating console video games rather than PC games.

Puzzle type of small games can be seen everywhere, but it's hard to find some creative ones with high playability. Teleportower (AKA: テレポー塔) belongs to the minority, which is a free and small 2D action puzzle game series with simple operations and 150 challenging stages, developed using Multimedia Fusion 2 Developer by 架歩 from Japan in 2010.

Tank Domination is a barrage (danmaku) type of small and free tank STG game developed by ASTRO PORT from Japan in 2006. It comes with omni-directional operation and very high game difficulty (a total of 4 difficulty levels for choice), and 13 stages for each difficulty. Its gaming difficulty is not only reflected in the way of the enemies' attack, also lies in that the author did not set a weapon upgrades system or a props system for the game.

MultiHero is an old fan-made, fast-paced 2D multiplayer fighting game developed in 2006. It's primarily inspired from the classic video game work Super Smash Brothers.