The game lacks any form of map that can be referenced at-will, only having one at save points. The map available at save points is also relatively misleading due to some rooms not telegraphing where they can actually be entered, most significantly with a specific room that is effectively two rooms for gameplay but one room for the purposes of the map.

The visual effects interfere with one of the bosses over and above any specific ability or inability for a graphics card to cope with the added load, making its attacks invisible.

Generally the boss fights could be better at communicating what actions are expected of the player, most especially the final boss which was the limit of my patience with the game.

I had to look up a walkthrough to be assured there was anything to find in the glitch zones after finding two of them empty, and I don't think I'd have made the leap of logic to determine how they allowed me to access the final zone if I had not looked up a walkthrough.