That was a fun and enjoyable mansion break. The mission can be completed in approximately 20 minutes, but there are a few well-hidden switches that make the experience a bit longer. The author is German and his English back in 2003 was not stellar, to say the least. However, the readables and objectives are pretty much straightforward, so I did not have any problems understanding where to go next. The architecture and design are basic, but there is some interesting and original use of textures. Where Hellerhouse shines the most is guard and light placement - there are a few spots inside the mansion that force you to carefully plan your next steps ahead and utilise available tools. DML fixes are required to launch this mission in New Dark. Recommended.

PS: Interestingly enough, this mission was released in late 2003 - a very dry year for Thief 1 FMs (only a few mediocre or at best average maps were released). This was when almost everyone jumped on the bandwagon of making levels for Thief 2. 17 years later Stringgod came back with a new FM called "Loser" - a rare example of a veteran DromEDer successfully releasing something after more than a decade.

Atmosphere: +15 points
Gameplay: +20 points
Story: +10 points
Originality Bonus: +5 points
Classic Experience Bonus: N/A
Cinematic Bonus: N/A
Audio Bonus: N/A
Debut FM Bonus: +5 points
1999 FM Bonus: N/A
Classic Era FM (1999-2003) Bonus: +5 points
Laziness Penalty: N/A
Bugs Penalty: N/A
AI Content Penalty: N/A
New Dark Penalty: N/A

Total Score: 60/100 or 6/10.