update 25/4/11: The intial translation appears to be complete now! Thanks to everyone who has contributed

A little consistency just needs to be applied throughout, though there are more important issues to attend to right now.
If more puzzle types appear, or there are phrases appearing that might be useful to have translated, post them here, and someone will translate.
Croco-puzzle Applet general usage instructions, and überraschungsrätsel instructions
"ABC-Box" (ABC-Box)
"ABCD-Rätsel" (ABCD puzzle)
"Arukone" (Arukone/Numberlink)
"Bahnhofe" (Railway Stations)
"Buchstabensalat" (Easy as ABC)
"Dominosuche" (Dominoes)
"Doppelblock" (Double Block)
"Doppelstern" (Star Battle)
"Fillomino" (Fillomino)
"Gebietssummen" (Area Sums)
"Hashi/Hashiwokakero" (Hashi/Bridges)
"Heyawake" (Heyawake)
"Hitori" (Hitori)
"Höhle" (Tunnels)
"Hochhäuser" (Skyscrapers)
"Inseln" (Islands)
"Japanische Summen" (Japanese Sums)
"Kakuro" (Kakuro)
"Killersudoku" (Killer Sudoku)
"Koralle" (Coral)
"Kropki" (Kropki)
"Laserrätsel" (Lasers)
"Magisches Labyrinth" (Magic Labyrinth)
"Magnetplatten" (Magnets)
"Masyu" (Masyu)
"Pentominosuche" (Pentomino Hunt)
"Pillenrätsel" (Pills)
"Pyramidenrätsel" (Number Pyramid)
"Rundwegrätsel" (Fences)
"Schlangenrätsel" (Snake)
"Slalom" (Slalom)
"Sternenhimmel" (Starry Night)
"Sudoku" (Irregular Sudoku)
"Tapa" (Tapa)
"Thermometer" (Thermometer)
"U-Bahn" (Subway Map)
"Vergleichssudoku" (Inequality Sudoku)
"Zeltlager" (Tents/Campsite)