Ok, I've made a log of every single tileset that I've altered, however trivially. I'm not sure how something like lightening/darkening a whole tileset would be percieved, or edits that are done to make the most of the 2 tileset per room limitation, but I'm listing everything.
Reading this may be a slight spoiler, though only in a very minor and forgettable way. I'd put spoiler tags on but I can't find them... If you want to avoid spoilers, please skip down to the "Author summary" list to see if you're one of the people I need permission from.
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Edits made in detail:
11 - Not Quite Dr's Underwater Lab - Nifflas - Vertical laser shooters added
16 - Brown House - Meppo - Furniture added, wallpaper added, 'Training Area' sign
37 - Moines - Yann 'Nurykabe' van der Cruyssen - More 'grey cement' tiles added
38 - Ramoneur - Yann 'Nurykabe' van der Cruyssen - Laser shooters added, spikes added, lava tile added (for layering purposes)
48 - Factory Converted by X_Sheep - Nifflas - Added mesh fence and futuristic looking pipes inspired by 'An Underwater Adventure'
50 - Rough Sea Landspace - Fredrik Andersson - Tileset UNchanged, trees converted to animated CO's
51 - WADF2 Practice by X_Sheep - Nifflas - Lava and water tiles added (for layering)
85 - etc - Not Quite Underwater Lab - Nifflas - Several copies made and darkened for lighting
107 - The Temple - Paul 'Ripen' Naurmowicz - depressed pressure plate added (modified floor tile)
122 - Strange Dream Science Facility - Sara Sandberg - Darkened copies of background tile for lighting effects. 'Light shining upwards' tiles copied and flipped, to create light tiles for the striplights
150 - Strange Dream 'The Manor' - Sara Sandberg - Glowing potion copied and colour changed. Striped background copied and colour changed. 'Stop Cock' sign tile added, and wall with ladder detail. Wrote 'Hello Mum' in unused tiles
151 - Strange Dream 'Ghost Town' - Sara Sandberg - Added extra chain tiles, drew in small 2x2 trees
153 - Strange Dream Well - Sara Sandberg - Added crude wall paintings
155 - Nowhere - Richard 'Arcturus' Dunn - Added weird hands to clock face. Created sewage pipe interior by manipulating an existing tile, created 1/2 tile wide channel in grey ground texture. Created tiled wall from the little 1/4 tile edge tiles of the red brick section.
163 - Wooden Blocks - Theo 'Theox' Swartz - Darkened, for lighing effect
246 - Strange Dream 'Cloud Buildings' - Sara Sandberg - Drew bridge tiles in spare space
250 - Strange Dream 'Dark Blue Forest' - Sara Sandberg - Added the red hot glowing tiles from Knytt
251 - Strange Dream 'Forest Village' - Sara Sandberg - Added extra buildings, clothes line with clothes, dirt hanging from celing, cracked floors
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Author Summary:
Nifflas - Not Quite Underwater Lab, Factory, WADF2 Practice
Sara Sandberg / Nifflas - Strange Dream Science Facility, SD The Manor, SD Ghost Town, SD Well, SD Cloud Buildings, SD Dark Blue Forest, SD Forest Village
Meppo - Brown House
Yann 'Nurykabe' van der Cruyssen - Moines, Ramoneur
Frederik Andersson - Rough Sea Landscape (trees converted to animated COs)
Paul 'Ripen' Naurmowicz - The Temple
Richard 'Arcturus' Dunn - Nowhere
Theo 'Theox' Swartz - Wooden Blocks (darkened whole set)