3/5 because of AI. Alien campaign is not hard because your enemies are stronger/better but because your teammates are retard. In Capture The Flag they just running around with flag instead of return it to get points. In Deathmatch they are just cannon fodder.
I beat EW5 (with all extra and trials) and must say I am very disappoited. Nice concept and graphics but gameplay deserves 1/5. Some stages are vey easy (f.e. last Trial) and some very difficult. Some spells are overpowered (regen wtf), heroes are pointless (they die really, really fast) and you can beat almost every stage with White Tiger + Omega Seal + Regen. My rating - 2/5 (1 for graphics)