I played the game and aside from the extremely long upgrades (12+ hours in most cases) and the fact you can only upgrade one thing at a time, and the incessant raids by the people who actually waste money on this game, I found it leisurely enough for a guy like me to be able to play it, leave it alone for a while and come back the next day and still not be able to do a dang thing. I only quit because I got tired of spending two weeks saving up for an upgrade only to have someone several people raid me while I was sleeping and lose all my progress and several expensive defense as well.
tl;dr It's just one of those many online games that you won't get anywhere unless you spend a lot of cash on.
