SudoKanard

 Battenburg Little Killer Sudoku Apply classic Sudoku rules. Whenever two odd and two even digits form a 2×2 chessboard pattern, a Battenburg marking is given. If there is no marking, the above pattern is not allowed. Each clue outside the grid indicates the sum of the digits contained in the cells in the direction of the corresponding arrow. Solve on Penpa: https://tinyurl.com/2ld3ktjp

 49     Standard Sudoku rules apply. Little Killer: a number next to an arrow is the sum of all digits along the diagonal pointed by the arrow. Killer: in each cage with a dashed outline, the sum of all digits is written in the top left corner of the cage. Fortress: each digit in a green cell is greater that all digits in orthogonally adjacent white cells. Thermo: along each thermometer, digits strictly increase starting from the bulb. Sandwich: each number in the left margin of the grid is the sum of all digits sandwiched between digits 1 and 9 in the corresponding row. Skyscrapers: each number on top of the grid is the number of buildings visible in the corresponding direction (digits are viewed as building heights and higher buildings block smaller buildings from view). Penpa link: https://git.io/J1jmU