Hot key for pause, skills and even quick restart(skip animation) may make this game more reasonable. Upgrage such as longer countdown, longer/stronger skills, or even hints may make it more acceptable.
Hm... I used steel claws in 3 games of arena yestarday and they were all 0 but it made 60 damage today. I think it would be unfair if steel claws, as well as other pet skills, are effective in arena.
Here my work for mortis, take the upper box at turn 3 and lower box at turn 5. Cut off yellow at turn 6 via lower path (left some space for green). Then, left green vs yellow and take the upper part (and cut off yellow if green cannot). Also, place some castles to block zombie attacking you. Later(around turn 18), other will be destoried by zombie. Keep putting all your men to cut off yellow. Around turn 27, yellow cannot break the layer. Finally, make it on turn 37.