Alphabet (アルファベット) is an escape room-style Flash game by Yomino Kagura. This iteration isn't as simple as the previous ones, as while the theme may be "the letters of the alphabet", the puzzles require more effort and outside box thinking. You'll need to solve them to get the code to the door out of the room.
Spikestuff here bypasses all of that hard thinking by already knowing the code and leaves the room as fast as possible.