Awesome game, but there are some issues:
Paladin's Holy Mace++ and Holy Mace+++ have no text descriptions.
Warlock's skill doesn't seem to work for me. It doesn't even change the Curse effects of Darkstrike to Enflames as described.
If you can't find where to go after beating the STOP sign, it is the top-right DOORWAY in the school. Unfortunately it is so GLITCHED that you can't simply walk into it! To get past the "invisible wall" that blocks the doorway, you have to "glitch" deep inside it with sprinting speed to reach the transition trigger. One reliable way is to start from the front side of the vending machines: Walk upwards to the machines until you are blocked and unable to advance further, walk straight right to the doorway, wait till your "sprint" (Z) meter is charged, hold the Z Key and then the Up Key to sprint into the doorway. You should be able to go in deep enough to reach the area-transition trigger and be the prompted to press "C".
If you see black screens with no text except occasional "Btye" (not "Byte") between levels, then it is the game that tries to show translations in your language but just gets broken. You may switch the in-game langusge to a different one to get some visible text.
Steps: Click the UI button with a "pause" icon in the top-left corner in game, and then the button in the top-right corner with a "gear" icon. You may see a big blank button in the middle above three options (with "sound", "music" and "battery" icons). Click that big blank button to choose a different language from a mouse-draggable list on which the language names are fortunately always visible. At least "English" works for me.
I've experienced troubles with the crystal podiums too, but it's weirder: the crystals could randomly deactivate themselves! I even once saw an already-activated crystal suddenly stop growing all by itself when I was just watching from a distance. I had to revisit all of the three again and again to make sure they were kept activated until the gate finally decided to let me pass, of course, after saving, refreshing and reloading the game for each attempt due to the other already-known detection bug. Is this related to the version of the Flash Player?
Another soft lock: On the 13. Different Direction level, if you pull down the first slider/lever/trigger thing across the long-way spiky pit, and then fall down to the spikes without ever activating the last checkpoint, or just ride on the remaining platforms that still keep moving to the left back to activate the previous checkpoint, you may get stuck at the left side of the long spiky pit as no new moving platforms will come.