buddhata:
I think all problems should say X to play... one should read it out if one can kill or if ko is the best one can do. Now it is easy to know what to do: to kill, to live (seki or 2 eyes) or to play (ko). If it is not ko then it will say to kill, not to play. Maybe an option would be to be able change the settings - if you want a hint then you get the description (to live, to make seki, to make ko or to kill) and if one wants a harder challenge it will just say: to play (and see for yourself). If you make ko while you can live, obviously that is an error, if you can make seki in sente will you can live in sente that also would be an error). Just my two cents...

Aumpa:
This one still says "to kill" instead of "to play".

dsatkas:
like in many other cases, the "solution" given, is that of a ok, not of a kill