In SK version, the text is sometimes too long for the menu or textboxes. When you encounter the very first chest, you can open it indefinitely to gain an unlimited amount of coins. The default arrowUP for jump is very weird choice. But its for free, and it looks nice.
+ plays nice + looks decent (check mods, they can change the experience from Half-Life 1 to looking like HL 2) - too much backtracking - worth like 8-10 hours of your time, after that gets repetitive - the story is not that good at all.