Gave a try to Hero Siege since I was able to get my steam key from Desura and, while I can see some potential for fun in the game, it left me quite unimpressed thanks to technical problems.
Playing in fullscreen, I was enduring some sort of screen-tearing on the top and bottom of my screen.
Playing in a window, a 480x320 window, I was having slow downs when a good amount of enemies were on screen at one point.
Gameplay wise, the shop mechanics that won't pause the game while you're buying a potion or some temporary buff is a bit annoying. If the shop window didn't cover so much of the screen it could be less annoying, probably.
I wasn't able to shoot in diagonal but only up/down and left/right and that feels quite restrictive.