MArcomage

It thing you should change the Enduring Effect to Attack 4 (i.e. Enduring (4) ) and then change the card effect from Attack 4 to Wall +4

Enduring keyword is only for attack, and the changes I suggest are going to do exactly the same thing

I really just wanted to see if you could do anything other than attack with Enduring

"Enduring - when card has this keyword, it also has a number next to this keyword. When such card is played and the last card played was same as this one, opponent will suffer additional damage equal to number next to Enduring."
this is from the game manual :)
although I must say it would be interesting having different effects with Enduring. However that could cause a bit of a problem in programming this. It would be too many variables for the system I think.

I like the idea, but as it is, this card definitely seems a bit imbalanced. It should cost a little more, in my opinion. Or be uncommon.

The balance is okay. It costs slightly more then Invaders, and does slightly more. Definately not uncommon.

Other Enduring effects (conceptually interesting) probably require a new keyword, though.