For the future you could go for a "show hint" option which gives out a tip..e.g puzzle one - hint: "blacks back rank looks very vulnerable". Don't know if this could be done just for the harder puzzles rather than them all. For board size - just a click to get a larger board would suit me. An FAQ would be a useful feature as you start to get more users.
"summary of table is good, but it seams that there are no white spaces after commas i.e ",black king", it would be better if ", black king". I was able to understand the pieces on the board using screen reader."
Hi, from RHP forum: That line now works in puzzle 21.I guess I made a typo earlier today. For puzzles with multiple solutions maybe you could cut them short?Take #19,you could stop where it's mate in two.People who found the previous moves will know anyway,but do mention it in the solution for the ones that didn't get it. Clicking squares is as good as drag 'n drop. 'Retry' button would be nice too.Good idea :) Maybe number the puzzles too?Perhaps it has no practical use but,for some odd reason,I find it looks nicer.
Show solution is a really good addition. I'd go for a slightly darker blue...buut only if you think so too. If the problems were numbered then it would be easier to give feedback if there's a question about one of the puzzles. I like the fact that it's not timed or graded...just practice the puzzle. And because you can't move the pieces around you have to visualize it. Now I'd like the option for a bigger board and also to be able to have the board more in the centre of my screen...I'm on firefox btw and it's all very solid. Keep up the good work!