"A fantasy d20-themed dungeon crawler", to quote DarkGod's comment. Inspired by Incursion by Julian Mensch. Made available under Open Game License. This is a non-profit fan project. No money is made. There are currently only two people working on the mod. However, we have released several beta versions so far.
This is the newest version (29/08/2016). This is the standalone version (T-Engine + module), just unpack and run. Highlights include: bug fixes, win condition, traps, journal.